diff --git a/crates/ide-agent/src/native/claude/translate.rs b/crates/ide-agent/src/native/claude/translate.rs
index ac8158f01..066be5f03 100644
--- a/crates/ide-agent/src/native/claude/translate.rs
+++ b/crates/ide-agent/src/native/claude/translate.rs
@@ -169,7 +169,7 @@ impl Translator {
                     Some("tool_use") => {
                         // The input streams after this: shown by name until the message has it.
                         let (id, name) = (str_of(&block, "id"), str_of(&block, "name"));
-                        if !id.is_empty() && !tools::is_plan(&name) && !(tools::is_agent(&name) && self.subagents) {
+                        if !(id.is_empty() || tools::is_plan(&name) || tools::is_agent(&name) && self.subagents) {
                             out.extend(self.ensure_call(&id, &name, &json!({}), &session));
                         }
                     }
diff --git a/crates/ide-host/src/data_dirs.rs b/crates/ide-host/src/data_dirs.rs
index 9c96c4153..b76b168cc 100644
--- a/crates/ide-host/src/data_dirs.rs
+++ b/crates/ide-host/src/data_dirs.rs
@@ -57,6 +57,7 @@ fn migrate_entries(data: &Path, local: &Path) {
         "notebook-runtime",
         "server",
         "java-usages-1.1.1.jar",
+        "java-usages-1.2.0.jar",
         "agents/registry.json",
     ]
     .into_iter()
@@ -298,6 +299,7 @@ mod tests {
             "agents/tools",
             "agents/registry.json",
             "java-usages-1.1.1.jar",
+            "java-usages-1.2.0.jar",
         ] {
             assert!(is_local(Path::new(entry)), "{entry}");
             assert_eq!(
diff --git a/crates/ide-language/src/lib.rs b/crates/ide-language/src/lib.rs
index 908e8315c..bd4fa6d59 100644
--- a/crates/ide-language/src/lib.rs
+++ b/crates/ide-language/src/lib.rs
@@ -15,9 +15,9 @@ mod syntax;
 pub use markers::marked_root;
 pub use registry::{FileTypes, LanguageRegistry};
 pub use syntax::{
-    CSS_CLASS, CSS_ID, CSS_VARIABLE, FileReference, Literal, LiteralKind, MAX_CACHED_TREES, MAX_PARSE_BYTES,
-    ParsedTree, SpellingKind, SpellingRegion, Syntax, SyntaxCache, SyntaxCacheStats, SyntaxHighlightKind,
-    SyntaxHighlights, TreeError, WebReference, WebReferenceKind, merge_visibility,
+    CSS_CLASS, CSS_ID, CSS_VARIABLE, ConfigurationKey, FileReference, Literal, LiteralKind, MAX_CACHED_TREES,
+    MAX_PARSE_BYTES, ParsedTree, SpellingKind, SpellingRegion, Syntax, SyntaxCache, SyntaxCacheStats,
+    SyntaxHighlightKind, SyntaxHighlights, TreeError, WebReference, WebReferenceKind, merge_visibility,
 };
 
 /// Parsed form of `languages/<id>.toml`. Backend-only; the UI gets [`LanguageInfo`].
diff --git a/crates/ide-language/src/syntax/configuration.rs b/crates/ide-language/src/syntax/configuration.rs
new file mode 100644
index 000000000..43c1cb5cf
--- /dev/null
+++ b/crates/ide-language/src/syntax/configuration.rs
@@ -0,0 +1,242 @@
+//! Source ranges for Spring-style configuration keys. This is a syntax index,
+//! not a YAML evaluator: aliases, merge keys and runtime profile precedence are
+//! intentionally left to the YAML server / application.
+use super::lines::LineIndex;
+use super::{ParsedTree, Syntax, TreeError};
+use ide_core::{LanguageId, Range};
+use tree_sitter::Node;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ConfigurationKey {
+    pub name: String,
+    pub range: Range,
+}
+
+impl Syntax {
+    pub fn configuration_keys(
+        &self,
+        language: &LanguageId,
+        text: &str,
+        cancelled: &dyn Fn() -> bool,
+    ) -> Result<Vec<ConfigurationKey>, TreeError> {
+        if language.as_str() == "properties" {
+            return Ok(properties(text));
+        }
+        self.with_parsed(language, text, cancelled, |tree| tree.configuration_keys(cancelled))
+    }
+}
+
+impl ParsedTree<'_> {
+    pub fn configuration_keys(&self, cancelled: &dyn Fn() -> bool) -> Vec<ConfigurationKey> {
+        let mut out = Vec::new();
+        if self.grammar == "yaml" {
+            yaml(self.tree.root_node(), "", self.text, &LineIndex::new(self.text), &mut out, cancelled, 0);
+        }
+        out
+    }
+}
+
+fn yaml(
+    node: Node<'_>,
+    prefix: &str,
+    text: &str,
+    lines: &LineIndex<'_>,
+    out: &mut Vec<ConfigurationKey>,
+    cancelled: &dyn Fn() -> bool,
+    depth: usize,
+) {
+    if depth > 64 || cancelled() || out.len() >= 20_000 {
+        return;
+    }
+    match node.kind() {
+        "block_mapping_pair" | "flow_pair" => {
+            let Some(key) = node.child_by_field_name("key") else { return };
+            let raw = &text[key.byte_range()];
+            if raw.contains('\n') {
+                return;
+            }
+            let name = if raw.starts_with('\'') && raw.ends_with('\'') {
+                raw[1..raw.len() - 1].replace("''", "'")
+            } else if raw.starts_with('"') {
+                // JSON escapes cover ordinary quoted configuration keys. Unsupported
+                // YAML-only escapes are skipped rather than indexed under a wrong key.
+                let Ok(name) = serde_json::from_str::<String>(raw) else { return };
+                name
+            } else {
+                if raw.contains(['\n', '{', '[', '*', '&', '!']) || raw == "<<" {
+                    return;
+                }
+                raw.to_owned()
+            };
+            if name.is_empty() {
+                return;
+            }
+            let name = if prefix.is_empty() {
+                name
+            } else if name.starts_with('[') {
+                format!("{prefix}{name}")
+            } else {
+                format!("{prefix}.{name}")
+            };
+            if name.len() > 1024 {
+                return;
+            }
+            out.push(ConfigurationKey { name: name.clone(), range: lines.range(key.start_byte(), key.end_byte()) });
+            if let Some(value) = node.child_by_field_name("value") {
+                yaml(value, &name, text, lines, out, cancelled, depth + 1);
+            }
+        }
+        "block_sequence" | "flow_sequence" => {
+            let mut cursor = node.walk();
+            for (i, child) in node.named_children(&mut cursor).filter(|n| n.kind() != "comment").enumerate() {
+                yaml(child, &format!("{prefix}[{i}]"), text, lines, out, cancelled, depth + 1);
+            }
+        }
+        // Do not descend into scalars, anchors or aliases.
+        "stream"
+        | "document"
+        | "block_node"
+        | "flow_node"
+        | "block_mapping"
+        | "flow_mapping"
+        | "block_sequence_item" => {
+            let mut cursor = node.walk();
+            for child in node.named_children(&mut cursor) {
+                yaml(child, prefix, text, lines, out, cancelled, depth + 1);
+            }
+        }
+        _ => {}
+    }
+}
+
+fn properties(text: &str) -> Vec<ConfigurationKey> {
+    let lines = LineIndex::new(text);
+    let mut out = Vec::new();
+    let mut logical = String::new();
+    let mut offsets = Vec::new();
+    let mut base = 0;
+    for line in text.split_inclusive('\n') {
+        let physical = line.trim_end_matches(['\r', '\n']);
+        let start = physical.len() - physical.trim_start_matches([' ', '\t', '\u{c}']).len();
+        let slice = &physical[start..];
+        if logical.is_empty() && (slice.is_empty() || slice.starts_with(['#', '!'])) {
+            base += line.len();
+            continue;
+        }
+        let continued = slice.bytes().rev().take_while(|b| *b == b'\\').count() % 2 == 1;
+        let end = physical.len() - usize::from(continued);
+        for (i, ch) in physical[start..end].char_indices() {
+            offsets.extend((0..ch.len_utf8()).map(|byte| base + start + i + byte));
+            logical.push(ch);
+        }
+        if !continued || base + line.len() == text.len() {
+            let mut escaped = false;
+            let key_end = logical
+                .char_indices()
+                .find_map(|(i, ch)| {
+                    if escaped {
+                        escaped = false;
+                        return None;
+                    }
+                    if ch == '\\' {
+                        escaped = true;
+                        return None;
+                    }
+                    matches!(ch, '=' | ':' | ' ' | '\t' | '\u{c}').then_some(i)
+                })
+                .unwrap_or(logical.len());
+            if key_end > 0
+                && key_end <= 1024
+                && let Some(name) = unescape_property(&logical[..key_end])
+            {
+                out.push(ConfigurationKey { name, range: lines.range(offsets[0], offsets[key_end - 1] + 1) });
+            }
+            logical.clear();
+            offsets.clear();
+        }
+        base += line.len();
+    }
+    out
+}
+
+fn unescape_property(raw: &str) -> Option<String> {
+    let mut chars = raw.chars();
+    let mut out = String::new();
+    while let Some(ch) = chars.next() {
+        if ch != '\\' {
+            out.push(ch);
+            continue;
+        }
+        match chars.next()? {
+            'u' => {
+                let hex: String = chars.by_ref().take(4).collect();
+                if hex.len() != 4 {
+                    return None;
+                }
+                out.push(char::from_u32(u32::from_str_radix(&hex, 16).ok()?)?);
+            }
+            't' => out.push('\t'),
+            'n' => out.push('\n'),
+            'r' => out.push('\r'),
+            'f' => out.push('\u{c}'),
+            ch => out.push(ch),
+        }
+    }
+    Some(out)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn yaml_structures_and_utf16() {
+        let text = "app:\n  'time-out': 1\n  hosts:\n    - url: a\n    - {url: b}\n  map: {east: {size: 2}}\n---\n\"app.name\": ok\n'😀': {port: 3}\n";
+        let keys = Syntax::new().configuration_keys(&LanguageId::new("yaml"), text, &|| false).unwrap();
+        let names: Vec<_> = keys.iter().map(|k| k.name.as_str()).collect();
+        assert_eq!(
+            names,
+            [
+                "app",
+                "app.time-out",
+                "app.hosts",
+                "app.hosts[0].url",
+                "app.hosts[1].url",
+                "app.map",
+                "app.map.east",
+                "app.map.east.size",
+                "app.name",
+                "😀",
+                "😀.port"
+            ]
+        );
+        assert_eq!(keys.last().unwrap().range.start.col, 7);
+    }
+    #[test]
+    fn aliases_and_values_are_not_configuration_keys() {
+        let keys = Syntax::new()
+            .configuration_keys(
+                &LanguageId::new("yaml"),
+                "base: &base {size: 1}\napp:\n  <<: *base\n  text: |\n    fake: key\n",
+                &|| false,
+            )
+            .unwrap();
+        assert_eq!(keys.iter().map(|k| k.name.as_str()).collect::<Vec<_>>(), ["base", "base.size", "app", "app.text"]);
+    }
+    #[test]
+    fn properties_unicode_ranges_and_eof_continuation() {
+        let keys = properties("app.中文=1\nlast\\\n");
+        assert_eq!(keys[0].range.end.col, 6);
+        assert_eq!(keys[1].name, "last");
+    }
+    #[test]
+    fn properties_escapes_continuations_and_comments() {
+        let keys = properties(
+            "# comment\r\napp.time\\\n  -out : 1\napp\\.name=ok\napp.\\u0061=2\nspace\\ key value\n!ignored=x\n",
+        );
+        assert_eq!(
+            keys.iter().map(|k| k.name.as_str()).collect::<Vec<_>>(),
+            ["app.time-out", "app.name", "app.a", "space key"]
+        );
+        assert_eq!(keys[0].range.end.line, 2);
+    }
+}
diff --git a/crates/ide-language/src/syntax/mod.rs b/crates/ide-language/src/syntax/mod.rs
index 5e22c169f..c578dbba8 100644
--- a/crates/ide-language/src/syntax/mod.rs
+++ b/crates/ide-language/src/syntax/mod.rs
@@ -1,6 +1,7 @@
 //! Tree-sitter driven structure: outline, folding, symbol tags, selection ranges, highlighting.
 
 mod cache;
+mod configuration;
 mod folding;
 mod grammars;
 mod highlight;
@@ -12,6 +13,7 @@ mod web;
 
 use crate::{FoldRange, LanguageConfig, LanguageRegistry, SymbolTag};
 pub use cache::{MAX_CACHED_TREES, SyntaxCache, SyntaxCacheStats};
+pub use configuration::ConfigurationKey;
 use grammars::{SPECS, Spec};
 pub use highlight::{SyntaxHighlightKind, SyntaxHighlights};
 use ide_core::{LanguageId, OutlineItem, Pos, Range};
diff --git a/crates/ide-lsp/src/jdtls.rs b/crates/ide-lsp/src/jdtls.rs
index 82a52ef41..8198a443c 100644
--- a/crates/ide-lsp/src/jdtls.rs
+++ b/crates/ide-lsp/src/jdtls.rs
@@ -18,6 +18,7 @@ use std::time::{Duration, Instant};
 
 const SERVER: &str = "jdtls";
 
+pub(crate) mod configuration;
 mod formatter;
 pub use formatter::configure_formatter;
 /// First start imports the Maven / Gradle model, which can take minutes.
diff --git a/crates/ide-lsp/src/jdtls/configuration.rs b/crates/ide-lsp/src/jdtls/configuration.rs
new file mode 100644
index 000000000..b11260ff4
--- /dev/null
+++ b/crates/ide-lsp/src/jdtls/configuration.rs
@@ -0,0 +1,416 @@
+//! Bridges configuration syntax to the app-owned JDT extension. No additional
+//! language server, build, or network request is needed. Disk parsing runs on a
+//! blocking worker; open buffers always win over cached disk contents.
+use super::*;
+use crate::text::Encoding;
+use crate::types::{References, ReferencesIncomplete};
+use crate::{DocSnap, Target};
+use ide_core::{Location, Pos};
+use ide_language::{ConfigurationKey, Syntax};
+use parking_lot::Mutex;
+use std::collections::HashMap;
+use std::sync::OnceLock;
+use std::time::SystemTime;
+
+const COMMAND: &str = "openidea.java.configuration";
+const MAX_BYTES: u64 = 2 * 1024 * 1024;
+const MAX_FILES: usize = 2000;
+const MAX_CACHED_KEYS: usize = 100_000;
+
+#[derive(Default)]
+pub(crate) struct ConfigurationCache {
+    files: HashMap<PathBuf, CachedFile>,
+}
+struct CachedFile {
+    stamp: (SystemTime, u64),
+    keys: Vec<ConfigurationKey>,
+}
+#[derive(Deserialize)]
+struct Pattern {
+    name: String,
+    relaxed: bool,
+}
+#[derive(Deserialize)]
+struct Response {
+    #[serde(default)]
+    locations: Vec<lsp_types::Location>,
+    #[serde(default)]
+    keys: Vec<Pattern>,
+    #[serde(default)]
+    roots: Vec<String>,
+    #[serde(default)]
+    incomplete: bool,
+}
+fn syntax() -> &'static Syntax {
+    static SYNTAX: OnceLock<Syntax> = OnceLock::new();
+    SYNTAX.get_or_init(Syntax::new)
+}
+fn language(path: &Path) -> Option<LanguageId> {
+    match path.extension()?.to_str()? {
+        "yaml" | "yml" => Some(LanguageId::new("yaml")),
+        "properties" => Some(LanguageId::new("properties")),
+        _ => None,
+    }
+}
+fn parts(key: &str) -> Vec<String> {
+    let mut out = Vec::new();
+    let mut part = String::new();
+    let mut chars = key.chars().peekable();
+    let mut bracket = false;
+    while let Some(ch) = chars.next() {
+        match ch {
+            '[' => {
+                if !part.is_empty() {
+                    out.push(std::mem::take(&mut part));
+                }
+                for ch in chars.by_ref() {
+                    if ch == ']' {
+                        break;
+                    }
+                    if !matches!(ch, '-' | '_') {
+                        part.extend(ch.to_lowercase());
+                    }
+                }
+                out.push(std::mem::take(&mut part));
+                bracket = true;
+            }
+            '.' => {
+                if !bracket {
+                    out.push(std::mem::take(&mut part));
+                }
+                bracket = false;
+            }
+            '-' | '_' => {}
+            ch => {
+                part.extend(ch.to_lowercase());
+                bracket = false;
+            }
+        }
+    }
+    if !part.is_empty() {
+        out.push(part);
+    }
+    out
+}
+fn matches(pattern: &Pattern, key: &str) -> bool {
+    if !pattern.relaxed {
+        return pattern.name == key;
+    }
+    let (a, b) = (parts(&pattern.name), parts(key));
+    a.len() == b.len() && a.iter().zip(b).all(|(a, b)| a == "*" || *a == b)
+}
+
+impl LspManager {
+    pub(crate) async fn configuration_navigation(
+        &self,
+        snap: &DocSnap,
+        pos: Pos,
+        usages: bool,
+        include_declaration: bool,
+        cancel: &CancellationToken,
+    ) -> IdeResult<Option<References>> {
+        if cancel.is_cancelled() {
+            return Err(IdeError::cancelled());
+        }
+        let config = language(&snap.path).is_some();
+        if !config && snap.language.as_str() != "java" {
+            return Ok(None);
+        }
+        // Definition in ordinary Java code remains JDT's definition. Reverse
+        // configuration navigation is offered on string expressions; field/config
+        // accessor usages are merged into the ordinary Find Usages response.
+        if !config && !usages {
+            let text = snap.text.as_str();
+            if !text.contains("Value") && !text.contains("getProperty") && !text.contains("getRequiredProperty") {
+                return Ok(None);
+            }
+        }
+        let key = if config {
+            let text = snap.text.as_str().to_owned();
+            if text.len() as u64 > MAX_BYTES {
+                return Ok(None);
+            }
+            let lang = language(&snap.path).expect("configuration language");
+            let cancelled = cancel.clone();
+            tokio::task::spawn_blocking(move || {
+                syntax()
+                    .configuration_keys(&lang, &text, &|| cancelled.is_cancelled())
+                    .ok()?
+                    .into_iter()
+                    .find(|key| key.range.start <= pos && pos < key.range.end)
+                    .map(|key| key.name)
+            })
+            .await
+            .ok()
+            .flatten()
+        } else {
+            None
+        };
+        if config && key.is_none() {
+            return Ok(None);
+        }
+        if config {
+            // Avoid starting a JVM for unrelated YAML (CI, Kubernetes, etc.).
+            let path = snap.path.clone();
+            let root = self.project_root.clone();
+            let java_project = tokio::task::spawn_blocking(move || {
+                path.ancestors().take_while(|p| p.starts_with(&root)).any(|p| {
+                    ["pom.xml", "build.gradle", "build.gradle.kts", ".classpath"]
+                        .iter()
+                        .any(|name| p.join(name).is_file())
+                })
+            })
+            .await
+            .unwrap_or(false);
+            if !java_project {
+                return Ok(None);
+            }
+        }
+        let result = self.configuration_query(snap, pos, key, usages, include_declaration, cancel).await;
+        match result {
+            Err(e) if cancel.is_cancelled() || e.kind == ErrorKind::Cancelled => Err(IdeError::cancelled()),
+            Err(e) => {
+                tracing::debug!("Configuration navigation unavailable; retaining native language navigation: {e}");
+                Ok(None)
+            }
+            result => result,
+        }
+    }
+
+    async fn configuration_query(
+        &self,
+        snap: &DocSnap,
+        pos: Pos,
+        key: Option<String>,
+        usages: bool,
+        include_declaration: bool,
+        cancel: &CancellationToken,
+    ) -> IdeResult<Option<References>> {
+        let (server, run) = self.jdtls(&snap.path, cancel).await?;
+        if !run.caps.read().commands().iter().any(|command| command == COMMAND) {
+            return Ok(None);
+        }
+        let target = Target { server: server.clone(), run };
+        let position = snap.text.ide_to_lsp(Encoding::Utf16, pos);
+        let response: Response = self
+            .call(
+                &target,
+                "workspace/executeCommand",
+                json!({
+                    "command": COMMAND, "arguments": [snap.uri, key, position.line, position.character, usages, include_declaration]
+                }),
+                Some(cancel),
+                crate::LONG_TIMEOUT,
+            )
+            .await?;
+        if cancel.is_cancelled() {
+            return Err(IdeError::cancelled());
+        }
+        if response.keys.is_empty() {
+            return Ok(response
+                .incomplete
+                .then(|| References { incomplete: Some(ReferencesIncomplete::FilesSkipped), ..Default::default() }));
+        }
+        let mut result = References {
+            locations: response.locations.iter().filter_map(|l| self.conv(Encoding::Utf16).location(l)).collect(),
+            incomplete: response.incomplete.then_some(ReferencesIncomplete::FilesSkipped),
+            ..Default::default()
+        };
+        self.note_virtual(&server, result.locations.iter().map(|l| l.uri.as_deref()));
+        if key.is_none() || usages {
+            let roots: Vec<PathBuf> = response.roots.iter().filter_map(|uri| super::project_path(uri)).collect();
+            let overlays: HashMap<PathBuf, String> = self
+                .docs
+                .lock()
+                .values()
+                .filter(|d| language(&d.path).is_some() && d.text.as_str().len() as u64 <= MAX_BYTES)
+                .map(|d| (d.canonical.clone(), d.text.as_str().to_owned()))
+                .collect();
+            let cache = self.configuration_cache.clone();
+            let cancelled = cancel.clone();
+            let keys = response.keys;
+            let files =
+                tokio::task::spawn_blocking(move || configuration_files(&roots, &keys, &overlays, &cache, &cancelled))
+                    .await
+                    .map_err(|_| IdeError::unavailable("configuration search worker stopped"))?;
+            result.locations.extend(files.locations);
+            result.incomplete = result.incomplete.or(files.incomplete);
+        }
+        if cancel.is_cancelled() || !self.docs.lock().values().any(|d| d.uri == snap.uri && d.version == snap.version) {
+            return Err(IdeError::cancelled());
+        }
+        if usages && key.is_some() && !include_declaration {
+            let source_path = self
+                .docs
+                .lock()
+                .values()
+                .find(|d| d.uri == snap.uri)
+                .map(|d| d.canonical.clone())
+                .unwrap_or_else(|| snap.path.clone());
+            result.locations.retain(|location| {
+                location.path.to_path_buf() != source_path || !(location.range.start <= pos && pos < location.range.end)
+            });
+        }
+        crate::convert::dedup_locations(&mut result.locations);
+        Ok(Some(result))
+    }
+}
+
+fn in_module(root: &Path, path: &Path) -> bool {
+    if !path.starts_with(root) {
+        return false;
+    }
+    for parent in path.parent().into_iter().flat_map(Path::ancestors).take_while(|p| *p != root) {
+        if matches!(
+            parent.file_name().and_then(|n| n.to_str()),
+            Some("target" | "build" | "node_modules" | ".git" | ".gradle")
+        ) {
+            return false;
+        }
+        if ["pom.xml", "build.gradle", "build.gradle.kts", ".classpath"].iter().any(|name| parent.join(name).is_file())
+        {
+            return false;
+        }
+    }
+    true
+}
+
+fn configuration_files(
+    roots: &[PathBuf],
+    patterns: &[Pattern],
+    overlays: &HashMap<PathBuf, String>,
+    cache: &Mutex<ConfigurationCache>,
+    cancel: &CancellationToken,
+) -> References {
+    let mut result = References::default();
+    let mut paths = std::collections::BTreeSet::new();
+    // Do not scan a source root twice when its enclosing module is also present.
+    let roots: Vec<_> =
+        roots.iter().filter(|root| !roots.iter().any(|other| other != *root && root.starts_with(other))).collect();
+    for root in &roots {
+        let module = (*root).clone();
+        let walker = ignore::WalkBuilder::new(root)
+            .follow_links(false)
+            .filter_entry(move |entry| {
+                if !entry.file_type().is_some_and(|t| t.is_dir()) {
+                    return true;
+                }
+                if entry.path() == module {
+                    return true;
+                }
+                if matches!(entry.file_name().to_str(), Some("target" | "build" | "node_modules" | ".git" | ".gradle"))
+                {
+                    return false;
+                }
+                // A sibling application's identical key must not leak into this module.
+                !["pom.xml", "build.gradle", "build.gradle.kts", ".classpath"]
+                    .iter()
+                    .any(|name| entry.path().join(name).is_file())
+            })
+            .build();
+        for (visited, entry) in walker.enumerate() {
+            if cancel.is_cancelled() {
+                return result;
+            }
+            if visited >= 50_000 || paths.len() >= MAX_FILES {
+                result.incomplete = Some(ReferencesIncomplete::TooManyFiles);
+                break;
+            }
+            match entry {
+                Ok(entry) if entry.file_type().is_some_and(|t| t.is_file()) && language(entry.path()).is_some() => {
+                    paths.insert(entry.into_path());
+                }
+                Err(_) => result.incomplete = Some(ReferencesIncomplete::FilesSkipped),
+                _ => {}
+            }
+        }
+    }
+    paths.extend(overlays.keys().filter(|p| roots.iter().any(|r| in_module(r, p))).cloned());
+    let mut cache = cache.lock();
+    if cache.files.len() > MAX_FILES {
+        cache.files.clear();
+    }
+    for path in paths {
+        if cancel.is_cancelled() {
+            return result;
+        }
+        let lang = language(&path).expect("configuration file");
+        let keys = if let Some(text) = overlays.get(&path) {
+            syntax().configuration_keys(&lang, text, &|| cancel.is_cancelled()).ok()
+        } else {
+            (|| {
+                let metadata = std::fs::metadata(&path).ok()?;
+                if metadata.len() > MAX_BYTES {
+                    return None;
+                }
+                let stamp = (metadata.modified().ok()?, metadata.len());
+                if let Some(file) = cache.files.get(&path).filter(|f| f.stamp == stamp) {
+                    return Some(file.keys.clone());
+                }
+                let text = std::fs::read_to_string(&path).ok()?;
+                let keys = syntax().configuration_keys(&lang, &text, &|| cancel.is_cancelled()).ok()?;
+                cache.files.remove(&path);
+                if cache.files.len() >= MAX_FILES
+                    || cache.files.values().map(|file| file.keys.len()).sum::<usize>() + keys.len() > MAX_CACHED_KEYS
+                {
+                    cache.files.clear();
+                }
+                cache.files.insert(path.clone(), CachedFile { stamp, keys: keys.clone() });
+                Some(keys)
+            })()
+        };
+        match keys {
+            Some(keys) => result.locations.extend(
+                keys.into_iter()
+                    .filter(|key| patterns.iter().any(|p| matches(p, &key.name)))
+                    .map(|key| Location::file(path.clone(), key.range)),
+            ),
+            None => result.incomplete = Some(ReferencesIncomplete::FilesSkipped),
+        }
+        if result.locations.len() >= MAX_FILES {
+            result.locations.truncate(MAX_FILES);
+            result.incomplete = Some(ReferencesIncomplete::TooManyFiles);
+            break;
+        }
+    }
+    result
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn file_cache_tracks_edits_overlays_removals_and_limits() {
+        let directory = tempfile::tempdir().unwrap();
+        let root = directory.path().to_path_buf();
+        let file = root.join("application.properties");
+        std::fs::write(&file, "app.port=1\n").unwrap();
+        let patterns = [Pattern { name: "app.port".into(), relaxed: true }];
+        let cache = Mutex::new(ConfigurationCache::default());
+        let cancel = CancellationToken::new();
+        let query = |overlays: &HashMap<PathBuf, String>| {
+            configuration_files(std::slice::from_ref(&root), &patterns, overlays, &cache, &cancel)
+        };
+        assert_eq!(query(&HashMap::new()).locations.len(), 1);
+        std::fs::write(&file, "app.other=12\n").unwrap();
+        assert!(query(&HashMap::new()).locations.is_empty());
+        assert_eq!(query(&HashMap::from([(file.clone(), "app.port=unsaved\n".into())])).locations.len(), 1);
+        std::fs::remove_file(&file).unwrap();
+        assert!(query(&HashMap::new()).locations.is_empty());
+        std::fs::write(&file, "x".repeat(MAX_BYTES as usize + 1)).unwrap();
+        assert_eq!(query(&HashMap::new()).incomplete, Some(ReferencesIncomplete::FilesSkipped));
+        cancel.cancel();
+        assert!(query(&HashMap::new()).locations.is_empty());
+    }
+
+    #[test]
+    fn relaxed_binding_keeps_boundaries() {
+        let pattern = Pattern { name: "app.clients[*].timeOut".into(), relaxed: true };
+        assert!(matches(&pattern, "app.clients[2].time-out"));
+        assert!(!matches(&pattern, "app.clientsTimeOut"));
+        let map = Pattern { name: "app.routes.*.url".into(), relaxed: true };
+        assert!(matches(&map, "app.routes[us.east].url"));
+        assert!(!matches(&map, "app.routes.us.east.url"));
+        assert!(!matches(&Pattern { name: "app.time-out".into(), relaxed: false }, "app.timeOut"));
+    }
+}
diff --git a/crates/ide-lsp/src/lib.rs b/crates/ide-lsp/src/lib.rs
index d8ead994b..45bef903a 100644
--- a/crates/ide-lsp/src/lib.rs
+++ b/crates/ide-lsp/src/lib.rs
@@ -179,6 +179,7 @@ pub struct LspManager {
     shutting_down: AtomicBool,
     execution_allowed: AtomicBool,
     java_usages_warned: AtomicBool,
+    configuration_cache: Arc<Mutex<jdtls::configuration::ConfigurationCache>>,
     /// `window/showMessage` texts already surfaced; servers repeat them on every restart/reconfigure.
     shown_messages: Mutex<HashSet<(String, String)>>,
     /// Virtual (non-`file:`) URIs a server returned, by the server that owns them.
@@ -313,6 +314,7 @@ impl LspManager {
             shutting_down: AtomicBool::new(false),
             execution_allowed: AtomicBool::new(true),
             java_usages_warned: AtomicBool::new(false),
+            configuration_cache: Arc::new(Mutex::new(Default::default())),
             shown_messages: Mutex::new(HashSet::new()),
             virtual_origins: Mutex::new(HashMap::new()),
             virtual_docs: Mutex::new(HashMap::new()),
@@ -1122,6 +1124,15 @@ impl LspManager {
     }
 
     pub async fn goto(&self, doc: DocId, pos: Pos, kind: GotoKind) -> IdeResult<Vec<Location>> {
+        if matches!(kind, GotoKind::Definition) {
+            let snap = self.snapshot(doc)?;
+            if let Some(result) =
+                self.configuration_navigation(&snap, pos, false, false, &CancellationToken::new()).await?
+                && !result.locations.is_empty()
+            {
+                return Ok(result.locations);
+            }
+        }
         let (method, cap, feature) = goto_method(kind);
         let (snap, targets) = self.doc_targets(doc, feature, |c| c.has(cap)).await?;
         self.goto_in(&snap, &targets, method, pos, None).await
@@ -1200,6 +1211,36 @@ impl LspManager {
         include_declaration: bool,
         project_wide: bool,
         cancel: CancellationToken,
+    ) -> IdeResult<References> {
+        let snap = self.snapshot(doc)?;
+        // Scoped probes back code lenses and bulk analysis. Keep their native cost;
+        // configuration indexing is reserved for explicit, project-wide usages.
+        let configuration = if project_wide || snap.language.as_str() != "java" {
+            self.configuration_navigation(&snap, pos, true, include_declaration, &cancel).await?
+        } else {
+            None
+        };
+        if snap.language.as_str() != "java"
+            && let Some(result) = configuration
+        {
+            return Ok(result);
+        }
+        let mut result = self.native_references(doc, pos, include_declaration, project_wide, cancel).await?;
+        if let Some(configuration) = configuration {
+            result.locations.extend(configuration.locations);
+            result.incomplete = result.incomplete.or(configuration.incomplete);
+            convert::dedup_locations(&mut result.locations);
+        }
+        Ok(result)
+    }
+
+    async fn native_references(
+        &self,
+        doc: DocId,
+        pos: Pos,
+        include_declaration: bool,
+        project_wide: bool,
+        cancel: CancellationToken,
     ) -> IdeResult<References> {
         let (snap, targets) = self.doc_targets(doc, "find references", |c| c.has("referencesProvider")).await?;
         // The extension preserves method identity before JDT collapses references to locations.
@@ -1212,7 +1253,7 @@ impl LspManager {
                 let t = &targets[0];
                 let extension_error = Mutex::new(None);
                 let query = || async {
-                    if cancel.is_cancelled() || !self.docs.lock().get(&doc).is_some_and(|d| d.version == snap.version) {
+                    if cancel.is_cancelled() || self.docs.lock().get(&doc).is_none_or(|d| d.version != snap.version) {
                         return Err(IdeError::cancelled());
                     }
                     let params = snap.pos_params(t, pos);
@@ -1240,7 +1281,7 @@ impl LspManager {
                         *extension_error.lock() = Some(e.clone());
                     }
                     let rows = result?;
-                    if cancel.is_cancelled() || !self.docs.lock().get(&doc).is_some_and(|d| d.version == snap.version) {
+                    if cancel.is_cancelled() || self.docs.lock().get(&doc).is_none_or(|d| d.version != snap.version) {
                         return Err(IdeError::cancelled());
                     }
                     let conv = self.conv(t.enc());
@@ -1266,7 +1307,7 @@ impl LspManager {
                     scope::Widened::only(first, empty, &t.server)
                 };
                 // A changed source also invalidates an earlier answer retained by scope widening.
-                if cancel.is_cancelled() || !self.docs.lock().get(&doc).is_some_and(|d| d.version == snap.version) {
+                if cancel.is_cancelled() || self.docs.lock().get(&doc).is_none_or(|d| d.version != snap.version) {
                     return Err(IdeError::cancelled());
                 }
                 // Scope widening can retain the first answer after a failed second query.
@@ -1292,7 +1333,7 @@ impl LspManager {
                 Err(e) => {
                     if e.kind == ErrorKind::Cancelled
                         || cancel.is_cancelled()
-                        || !self.docs.lock().get(&doc).is_some_and(|d| d.version == snap.version)
+                        || self.docs.lock().get(&doc).is_none_or(|d| d.version != snap.version)
                     {
                         return Err(IdeError::cancelled());
                     }
diff --git a/crates/ide-lsp/tests/mock_server.rs b/crates/ide-lsp/tests/mock_server.rs
index a473e8cbc..b33110a20 100644
--- a/crates/ide-lsp/tests/mock_server.rs
+++ b/crates/ide-lsp/tests/mock_server.rs
@@ -2916,3 +2916,92 @@ async fn clang_tidy_config_for_a_later_opened_file_warns_on_a_running_server() {
     assert_eq!(h.mgr.servers().len(), 1);
     h.mgr.shutdown_all().await;
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn configuration_definition_uses_java_without_yaml_definition_capability() {
+    let mut caps = incremental_caps();
+    caps["executeCommandProvider"] = json!({"commands": ["openidea.java.configuration"]});
+    let h = harness_for("java", "java", &[("jdtls", caps)], &[]);
+    std::fs::write(h.root.join("pom.xml"), "<project/>").unwrap();
+    let s = h.launcher.state("jdtls");
+    let target = uri_of(&h.root.join("Settings.java"));
+    s.respond("workspace/executeCommand", json!({
+        "locations": [{"uri": target, "range": {"start": {"line": 2, "character": 4}, "end": {"line": 2, "character": 11}}}],
+        "keys": [{"name": "app.timeOut", "relaxed": true}], "roots": []
+    }));
+    let path = h.root.join("application.yml");
+    let doc = DocId::next();
+    h.mgr.did_open(doc, &path, &LanguageId::new("yaml"), 1, "app:\n  time-out: 5\n");
+    let locations = h.mgr.goto(doc, Pos::new(1, 4), GotoKind::Definition).await.unwrap();
+    assert_eq!(locations.len(), 1);
+    assert_eq!(locations[0].range.start, Pos::new(2, 4));
+    assert_eq!(s.requested("workspace/executeCommand")[0]["arguments"][1], "app.time-out");
+    assert!(s.requested("textDocument/definition").is_empty());
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn configuration_usages_merge_native_and_unsaved_profiles_without_sibling_modules() {
+    let mut caps = incremental_caps();
+    caps["executeCommandProvider"] = json!({"commands": ["openidea.java.configuration"]});
+    let h = harness_for("java", "java", &[("jdtls", caps)], &[]);
+    let s = h.launcher.state("jdtls");
+    let (doc, path) = h.open("Settings.java", "int timeOut;");
+    h.wait_status("jdtls", ServerStatus::Ready).await;
+    let root = uri_of(&h.root);
+    s.respond(
+        "workspace/executeCommand",
+        json!({
+            "locations": [], "keys": [{"name": "app.timeOut", "relaxed": true}], "roots": [root]
+        }),
+    );
+    s.respond(
+        "textDocument/references",
+        json!([{"uri": uri_of(&path), "range": {
+            "start": {"line": 3, "character": 0}, "end": {"line": 3, "character": 7}
+        }}]),
+    );
+    std::fs::write(h.root.join("application.yml"), "app:\n  time-out: 1\n").unwrap();
+    std::fs::write(h.root.join("application-prod.properties"), "app.time-out=2\n").unwrap();
+    let overlay = h.root.join("application-dev.yml");
+    std::fs::write(&overlay, "app:\n  old: 3\n").unwrap();
+    h.mgr.did_open(DocId::next(), &overlay, &LanguageId::new("yaml"), 1, "app:\n  time-out: 3\n");
+    let sibling = h.root.join("other");
+    std::fs::create_dir(&sibling).unwrap();
+    std::fs::write(sibling.join("pom.xml"), "<project/>").unwrap();
+    std::fs::write(sibling.join("application.yml"), "app:\n  time-out: wrong\n").unwrap();
+    h.mgr.did_open(
+        DocId::next(),
+        &sibling.join("application.yml"),
+        &LanguageId::new("yaml"),
+        1,
+        "app:\n  time-out: still-wrong\n",
+    );
+    let scoped = h.mgr.references(doc, Pos::new(0, 6), false, false, Default::default()).await.unwrap();
+    assert_eq!(scoped.locations.len(), 1);
+    assert!(s.requested("workspace/executeCommand").is_empty());
+    let refs = h.mgr.references(doc, Pos::new(0, 6), false, true, Default::default()).await.unwrap();
+    assert_eq!(refs.locations.len(), 4, "{refs:?}");
+    assert!(refs.locations.iter().all(|l| !l.path.to_path_buf().starts_with(&sibling)));
+    assert!(refs.locations.iter().any(|l| l.path.to_path_buf() == overlay));
+    assert_eq!(refs.incomplete, None);
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn configuration_extension_failure_preserves_native_java_navigation() {
+    let mut caps = incremental_caps();
+    caps["executeCommandProvider"] = json!({"commands": ["openidea.java.configuration"]});
+    let h = harness_for("java", "java", &[("jdtls", caps)], &[]);
+    let s = h.launcher.state("jdtls");
+    let (doc, path) = h.open("Settings.java", "@Value(\"${app.port}\") int port;");
+    h.wait_status("jdtls", ServerStatus::Ready).await;
+    s.errors.lock().insert("workspace/executeCommand".into(), (-32603, "old server".into()));
+    s.respond(
+        "textDocument/definition",
+        json!({"uri": uri_of(&path), "range": {
+            "start": {"line": 0, "character": 1}, "end": {"line": 0, "character": 6}
+        }}),
+    );
+    let result = h.mgr.goto(doc, Pos::new(0, 2), GotoKind::Definition).await.unwrap();
+    assert_eq!(result.len(), 1);
+    assert_eq!(s.requested("textDocument/definition").len(), 1);
+}
diff --git a/crates/ide-sdk/src/java.rs b/crates/ide-sdk/src/java.rs
index 56d81ecf7..9120b0e5f 100644
--- a/crates/ide-sdk/src/java.rs
+++ b/crates/ide-sdk/src/java.rs
@@ -1173,7 +1173,7 @@ mod kotlin_bridge_bundle_tests {
 
 /// Installs the app-owned JDT LS command bundle, falling back to ordinary LSP on IO failure.
 pub fn usages_bundle(data_dir: &Path) -> Option<PathBuf> {
-    let extension = data_dir.join("java-usages-1.1.1.jar");
+    let extension = data_dir.join("java-usages-1.2.0.jar");
     let bytes = include_bytes!("../../../plugins/java-usages/openidea-java-usages.jar");
     if std::fs::read(&extension).is_ok_and(|old| old == bytes) {
         clean_usages_bundles(data_dir, &extension);
diff --git a/crates/ide-syntax/src/jvm.rs b/crates/ide-syntax/src/jvm.rs
index 9da0f7b46..88e3c7ca6 100644
--- a/crates/ide-syntax/src/jvm.rs
+++ b/crates/ide-syntax/src/jvm.rs
@@ -159,7 +159,7 @@ impl StructureService {
             let runnable = body.is_some_and(|b| {
                 members(*b).into_iter().any(|n| {
                     if !matches!(n.kind(), "method_declaration" | "function_declaration")
-                        || !n.child_by_field_name("name").is_some_and(|id| text(id, snap.text) == "main")
+                        || n.child_by_field_name("name").is_none_or(|id| text(id, snap.text) != "main")
                     {
                         return false;
                     }
diff --git a/plugins/java-usages/CONFIGURATION.md b/plugins/java-usages/CONFIGURATION.md
new file mode 100644
index 000000000..fae42f40c
--- /dev/null
+++ b/plugins/java-usages/CONFIGURATION.md
@@ -0,0 +1,114 @@
+# Spring configuration navigation
+
+`openidea.java.configuration` bridges YAML / properties to the existing JDT LS
+Java model. It is bundled with the Java usages extension; it does not install a
+second language server, run a build, change the application's dependencies, or
+connect to external configuration services.
+
+## Editor behavior
+
+- **Go to Definition** on a YAML / properties key opens binding members and
+  literal consumers in Java. Multiple matches use the existing location chooser.
+- **Go to Definition** inside a Java `@Value` placeholder or a constant
+  `Environment.getProperty` / `getRequiredProperty` argument opens matching
+  configuration keys. Ordinary Java definition navigation remains native.
+- **Find Usages** joins configuration declarations, property consumers, and Java
+  references to associated binding members. Java's existing reference results and
+  read/write classifications are retained.
+- Open editor contents take precedence over disk. All matching profiles/documents
+  are shown; navigation does not claim to know the runtime effective value.
+- Missing or older extension bundles preserve native language-server behavior.
+  YAML aliases still use the YAML server's anchor navigation.
+
+## Association sources
+
+The Java command resolves annotation and method identities with JDT bindings:
+
+- `@ConfigurationProperties` on classes and factory methods, including inherited
+  members, nested objects, records, constructor-only parameters / `@Name`, arrays,
+  collections and maps. Binder keys use relaxed spelling while retaining path
+  boundaries. Indexed collection positions and arbitrary map keys use wildcards.
+- `@Value("${key:default}")`, including constant annotation values and nested
+  default placeholders.
+- Literal or compile-time constant keys passed to Spring's `PropertyResolver`
+  methods, including through `Environment`. Unrelated methods with the same name
+  and non-Spring annotations are excluded.
+- Dependency JAR `META-INF/spring-configuration-metadata.json` and
+  `additional-spring-configuration-metadata.json`. The closest group, source
+  type, and source method locate a member or its owning class. Source attachments
+  and JDT class-file/decompiler navigation use the existing virtual-document path.
+- The same metadata files in source roots and `src/main/resources`.
+
+YAML key ranges come from the bundled tree-sitter grammar, including nested/flow
+mappings, sequences, quoted keys and multiple documents. Properties support
+escaped keys, Unicode escapes and logical-line continuations. Ranges crossing
+IPC are UTF-16. No new IPC type or frontend provider is required.
+
+## Scope and costs
+
+The command uses the selected JDT project's resolved package roots, including
+source dependencies and its dependency JARs. Configuration search includes those
+modules, skips nested independent modules and build output, and honors ignore
+files for disk discovery. It does not guess a global association from matching
+text in unrelated projects.
+
+Indexing is lazy. The first explicit navigation/search builds a compact snapshot;
+ordinary typing, code-lens probes and bulk scoped reference analysis do not start indexing. At most eight project snapshots are
+retained, with a shared 100,000-association retention cap. Records contain property names, element handles and source locations;
+ASTs and bindings are discarded after indexing. A lexical prefilter avoids AST
+construction for ordinary Java units, but every accepted association is resolved
+semantically. Warm requests reuse the snapshot. Java model/reconcile changes
+invalidate it conservatively, including dependent-type changes; open working-copy
+content fingerprints also prevent stale answers before reconciliation. This is
+**snapshot invalidation**, not a fully incremental Java semantic index.
+
+Metadata/JAR timestamps are checked before reuse. The client caches parsed disk
+configuration files by modification time and size (at most 100,000 cached keys), overlays open buffers, and
+performs bounded discovery/parsing on a blocking worker. It does not continuously
+watch or parse an additional copy of the entire workspace.
+
+Bounds: 20,000 Java units, 100,000 associations per snapshot, 2 MiB per candidate
+metadata/configuration file (Java source: 2M UTF-16 units), 1,024-character property names, 2,000 configuration files/results, 50,000 filesystem
+entries per root, and depth limits on recursive bindings/YAML. Java requests and
+references are cancellable. File/association scan limits and unreadable files carry the
+existing incomplete-result indicator; unsupported syntax keys are omitted. First navigation can take seconds on a
+cold project; classpath import and source download remain owned by JDT LS.
+
+## Deliberate limits
+
+This is Java/Spring property navigation, not full IntelliJ Spring support. It
+cannot infer dynamically constructed names, custom configuration APIs/annotations,
+remote-only configuration, arbitrary SpEL evaluation, YAML merge/alias expansion,
+or custom Spring converters that change the binding shape. Kotlin is not indexed
+by this Java bundle. YAML-only quoted-string escape forms that cannot be decoded
+safely are skipped. Properties surrogate-pair escapes are not decoded as keys.
+A missing source attachment may navigate to the decompiled owning class when JDT
+cannot provide an exact member range. Binding members are navigation candidates;
+the feature does not validate whether Spring will successfully bind a bean at
+runtime or resolve profile/precedence rules.
+
+## Verification
+
+Use the JDT LS distribution / Java version documented in [README](README.md).
+
+```sh
+python3 plugins/java-usages/build.py /path/to/jdtls
+python3 plugins/java-usages/tests/configuration.py /path/to/jdtls
+OPENIDEA_CONFIGURATION_STRESS=1 python3 plugins/java-usages/tests/configuration.py /path/to/jdtls
+OPENIDEA_SPRING_BOOT_JAR=/path/to/spring-boot-autoconfigure.jar python3 plugins/java-usages/tests/configuration.py /path/to/jdtls
+cargo test -p ide-language -p ide-lsp
+```
+
+The isolated real-server harness covers custom bindings, inheritance, nesting,
+collections/maps, records, constructor aliases, factory methods, consumers,
+constant keys, negative identity matches, dependency metadata/source locations,
+reverse queries, and unsaved-change/close invalidation. Optional stress fixtures
+add 3,000 ordinary units and 100 binding classes; output includes cold/warm/edit
+latencies for the JDT command only, excluding server import, UI and configuration-file discovery. The optional actual Spring Boot JAR checks `server.port`,
+`spring.datasource.url` and `spring.jackson.date-format` through dependency
+metadata. No user's project is compiled or modified by the harness.
+
+Rust tests cover configuration syntax/ranges and the actual manager bridge:
+YAML navigation without YAML definition capabilities, Java native fallback,
+reference merging, profiles, open-buffer overlays and sibling-module exclusion.
+Existing Java usages / read-write integration harnesses remain regression checks.
diff --git a/plugins/java-usages/MANIFEST.MF b/plugins/java-usages/MANIFEST.MF
index 1775ddec8..7ec5b7f32 100644
--- a/plugins/java-usages/MANIFEST.MF
+++ b/plugins/java-usages/MANIFEST.MF
@@ -2,9 +2,9 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: OpenIDEA Java usages
 Bundle-SymbolicName: ai.openidea.usages;singleton:=true
-Bundle-Version: 1.1.1
+Bundle-Version: 1.2.0
 Bundle-RequiredExecutionEnvironment: JavaSE-21
 Require-Bundle: org.eclipse.jdt.ls.core,org.eclipse.jdt.core,
  org.eclipse.jdt.core.manipulation,org.eclipse.core.runtime,
- org.eclipse.lsp4j
+ org.eclipse.lsp4j,org.eclipse.core.resources,com.google.gson
 
diff --git a/plugins/java-usages/README.md b/plugins/java-usages/README.md
index 5be955109..6f8203215 100644
--- a/plugins/java-usages/README.md
+++ b/plugins/java-usages/README.md
@@ -1,4 +1,6 @@
-# Semantic Java usages
+# Semantic Java usages and configuration navigation
+
+Spring YAML / properties navigation is described in [CONFIGURATION.md](CONFIGURATION.md).
 
 The app-owned OSGi command `openidea.java.usages` returns `{location, kind, access}`.
 `kind` retains field/getter/setter/unknown identity for compatibility. Optional
@@ -55,7 +57,7 @@ is not a claim of full IntelliJ feature parity.
 ## Rebuild and delivery
 
 The checked-in jar is embedded by ide-sdk `include_bytes!`, installed as
-`java-usages-1.1.1.jar`, and added alongside existing initialization bundles.
+`java-usages-1.2.0.jar`, and added alongside existing initialization bundles.
 Users need no compiler, Maven or Python. Manifest/install version must change
 when replacing the bundle because OSGi caches bundles.
 
@@ -64,8 +66,10 @@ Use its shipped ECJ and plugin jars, with Java 25; emitted bytecode targets Java
 The build uses sorted inputs and fixed zip timestamps and does not resolve Maven
 artifacts. Check the extracted distribution against `build-dependencies.sha256`
 from its root (`sha256sum -c /path/to/build-dependencies.sha256`). Build twice
-and compare SHA-256. The 1.1.1 output is
+and compare SHA-256. The prior 1.1.1 output was
 `1e569939cba22c7db6e2c9b53de2a4c10ccaabe762a51427119a04af3d974ae4`.
+Version 1.2.0 adds the configuration command; its reproducible SHA-256 is
+`9140f1d2ecf27eadfe66b40a17daa18a08a65927ebef79456ba55d486ce5eeba`.
 
 ```sh
 export PATH=/path/to/jdk25/bin:$PATH
diff --git a/plugins/java-usages/openidea-java-usages.jar b/plugins/java-usages/openidea-java-usages.jar
index 0eee59354..3f521b3a3 100644
Binary files a/plugins/java-usages/openidea-java-usages.jar and b/plugins/java-usages/openidea-java-usages.jar differ
diff --git a/plugins/java-usages/plugin.xml b/plugins/java-usages/plugin.xml
index f654f9def..dad7e8d8c 100644
--- a/plugins/java-usages/plugin.xml
+++ b/plugins/java-usages/plugin.xml
@@ -4,5 +4,8 @@
     <delegateCommandHandler class="ai.openidea.usages.UsagesCommand">
       <command id="openidea.java.usages"/>
     </delegateCommandHandler>
+    <delegateCommandHandler class="ai.openidea.configuration.ConfigurationCommand">
+      <command id="openidea.java.configuration"/>
+    </delegateCommandHandler>
   </extension>
 </plugin>
diff --git a/plugins/java-usages/src/ai/openidea/configuration/ConfigurationCommand.java b/plugins/java-usages/src/ai/openidea/configuration/ConfigurationCommand.java
new file mode 100644
index 000000000..39fce3a9e
--- /dev/null
+++ b/plugins/java-usages/src/ai/openidea/configuration/ConfigurationCommand.java
@@ -0,0 +1,525 @@
+package ai.openidea.configuration;
+
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.zip.ZipFile;
+import com.google.gson.*;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.OperationCanceledException;
+import org.eclipse.jdt.core.*;
+import org.eclipse.jdt.core.dom.*;
+import org.eclipse.jdt.ls.core.internal.IDelegateCommandHandler;
+import org.eclipse.jdt.ls.core.internal.JDTUtils;
+import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
+import org.eclipse.jdt.ls.core.internal.handlers.ReferencesHandler;
+import org.eclipse.lsp4j.Location;
+
+/** On-demand configuration index, scoped by JDT's resolved source/class path.
+ * Cached records contain strings and locations, never ASTs or bindings. Java model
+ * changes invalidate snapshots, including unsaved working copies and classpath edits.
+ */
+public final class ConfigurationCommand implements IDelegateCommandHandler {
+    private static final String PROPERTIES = "org.springframework.boot.context.properties.ConfigurationProperties";
+    private static final String VALUE = "org.springframework.beans.factory.annotation.Value";
+    private static final String RESOLVER = "org.springframework.core.env.PropertyResolver";
+    private static final int MAX_UNITS = 20_000, MAX_ENTRIES = 100_000, MAX_BYTES = 2 * 1024 * 1024;
+    private static final AtomicLong REVISION = new AtomicLong();
+    private static final Map<String, Index> CACHE = new LinkedHashMap<>();
+    static { JavaCore.addElementChangedListener(event -> REVISION.incrementAndGet(), ElementChangedEvent.POST_CHANGE | ElementChangedEvent.POST_RECONCILE); }
+
+    private record Entry(String name, String handle, Location location, boolean relaxed) {}
+    private record FileStamp(java.nio.file.attribute.FileTime modified, long size) {}
+    private static FileStamp stamp(Path path) {
+        try { return new FileStamp(Files.getLastModifiedTime(path), Files.size(path)); }
+        catch (java.io.IOException e) { return new FileStamp(null, -1); }
+    }
+    private record Index(long revision, String workingCopies, List<Entry> entries, List<String> roots,
+            Map<Path, FileStamp> files, boolean incomplete, int parsed) {}
+
+    @Override
+    public Object executeCommand(String command, List<Object> args, IProgressMonitor monitor) throws Exception {
+        String uri = (String) args.get(0);
+        String key = args.get(1) instanceof String s ? s : null;
+        int line = ((Number) args.get(2)).intValue(), column = ((Number) args.get(3)).intValue();
+        boolean references = args.size() > 4 && Boolean.TRUE.equals(args.get(4));
+        boolean declarations = args.size() > 5 && Boolean.TRUE.equals(args.get(5));
+        ITypeRoot selectedRoot = JDTUtils.resolveTypeRoot(uri);
+        IJavaProject project = selectedRoot == null ? project(uri) : selectedRoot.getJavaProject();
+        if (project == null) return Map.of("locations", List.of(), "keys", List.of(), "roots", List.of(), "incomplete", true);
+        Index index = index(project, monitor);
+        Set<Map<String, Object>> keys = new LinkedHashSet<>();
+        Set<Location> locations = new LinkedHashSet<>();
+        String selected = null;
+        if (key == null && selectedRoot != null && references) {
+            var element = JDTUtils.findElementAtSelection(selectedRoot, line, column,
+                    JavaLanguageServerPlugin.getPreferencesManager(), monitor);
+            if (element != null) selected = element.getHandleIdentifier();
+        }
+        for (Entry entry : index.entries) {
+            check(monitor);
+            Location location = entry.location;
+            if (key != null) {
+                if (matches(entry.name, key, entry.relaxed)) {
+                    if (!entry.handle.isEmpty() && references) {
+                        var element = JavaCore.create(entry.handle);
+                        if (element != null && element.exists()) {
+                            List<Location> usages = new ArrayList<>();
+                            new ReferencesHandler(JavaLanguageServerPlugin.getPreferencesManager())
+                                .search(element, usages, monitor, declarations);
+                            locations.addAll(usages);
+                        }
+                    } else {
+                        if (location == null && !entry.handle.isEmpty()) location = location(entry.handle);
+                        if (location != null) locations.add(location);
+                    }
+                    keys.add(Map.of("name", entry.name, "relaxed", entry.relaxed));
+                }
+            } else if ((!entry.handle.isEmpty() && entry.handle.equals(selected)) ||
+                    (location != null && sameUri(location.getUri(), uri) && contains(location, line, column))) {
+                keys.add(Map.of("name", entry.name, "relaxed", entry.relaxed));
+            }
+            if (locations.size() >= 2000) break;
+        }
+        // Reverse Find Usages joins property consumers with the binding member's
+        // ordinary Java usages. Definition on a string only returns config keys.
+        if (key == null && references && !keys.isEmpty()) {
+            Set<String> searched = new HashSet<>();
+            for (Entry entry : index.entries) {
+                check(monitor);
+                boolean related = keys.stream().anyMatch(pattern ->
+                    matches(entry.name, (String) pattern.get("name"), entry.relaxed) ||
+                    matches((String) pattern.get("name"), entry.name, Boolean.TRUE.equals(pattern.get("relaxed"))));
+                if (!related) continue;
+                if (entry.location != null) locations.add(entry.location);
+                else if (!entry.handle.isEmpty() && searched.add(entry.handle)) {
+                    IJavaElement element = JavaCore.create(entry.handle);
+                    if (element != null && element.exists()) {
+                        List<Location> usages = new ArrayList<>();
+                        new ReferencesHandler(JavaLanguageServerPlugin.getPreferencesManager()).search(element, usages, monitor, declarations);
+                        locations.addAll(usages);
+                    }
+                }
+                if (locations.size() >= 2000) break;
+            }
+        }
+        return Map.of("locations", locations, "keys", keys, "roots", index.roots,
+                "incomplete", index.incomplete || locations.size() >= 2000,
+                "parsedUnits", index.parsed, "revision", index.revision);
+    }
+
+    private static boolean sameUri(String a, String b) {
+        URI left = URI.create(a), right = URI.create(b);
+        if (left.equals(right)) return true;
+        if (!"file".equals(left.getScheme()) || !"file".equals(right.getScheme())) return false;
+        try { return Path.of(left).toFile().getCanonicalFile().equals(Path.of(right).toFile().getCanonicalFile()); }
+        catch (java.io.IOException e) { return false; }
+    }
+    private static boolean contains(Location l, int line, int col) {
+        var r = l.getRange();
+        return (line > r.getStart().getLine() || line == r.getStart().getLine() && col >= r.getStart().getCharacter()) &&
+                (line < r.getEnd().getLine() || line == r.getEnd().getLine() && col < r.getEnd().getCharacter());
+    }
+    private static void check(IProgressMonitor monitor) { if (monitor.isCanceled()) throw new OperationCanceledException(); }
+    private static IJavaProject project(String uri) {
+        Path path;
+        try { path = Path.of(URI.create(uri)).toFile().getCanonicalFile().toPath(); } catch (Exception e) { return null; }
+        IJavaProject best = null;
+        int length = -1;
+        for (var p : ResourcesPlugin.getWorkspace().getRoot().getProjects()) {
+            if (!p.isOpen() || p.getLocation() == null) continue;
+            var candidate = JavaCore.create(p);
+            Path root;
+            try { root = p.getLocation().toFile().getCanonicalFile().toPath(); } catch (java.io.IOException e) { continue; }
+            if (candidate.exists() && path.startsWith(root) && root.getNameCount() > length) {
+                best = candidate; length = root.getNameCount();
+            }
+        }
+        return best;
+    }
+    private static Location location(String handle) throws JavaModelException {
+        IJavaElement element = JavaCore.create(handle);
+        if (element == null || !element.exists()) return null;
+        Location result = JDTUtils.toLocation(element);
+        if (result == null && element instanceof IMember member && member.getClassFile() != null)
+            result = JDTUtils.toLocation(member.getClassFile());
+        return result;
+    }
+
+    private static synchronized Index index(IJavaProject project, IProgressMonitor monitor) throws Exception {
+        long revision = REVISION.get();
+        String id = project.getHandleIdentifier();
+        Map<String, ICompilationUnit> copies = new TreeMap<>();
+        for (ICompilationUnit copy : JavaCore.getWorkingCopies(null)) copies.put(copy.getPrimary().getHandleIdentifier(), copy);
+        for (ICompilationUnit copy : JavaCore.getWorkingCopies(JavaLanguageServerPlugin.getInstance().getWorkingCopyOwner()))
+            copies.put(copy.getPrimary().getHandleIdentifier(), copy);
+        var digest = java.security.MessageDigest.getInstance("SHA-256");
+        for (var entry : copies.entrySet()) {
+            check(monitor);
+            digest.update(entry.getKey().getBytes(java.nio.charset.StandardCharsets.UTF_8));
+            String source = entry.getValue().getSource();
+            if (source != null) digest.update(source.getBytes(java.nio.charset.StandardCharsets.UTF_8));
+        }
+        String workingCopies = HexFormat.of().formatHex(digest.digest());
+        Index cached = CACHE.get(id);
+        if (cached != null && cached.revision == revision && cached.workingCopies.equals(workingCopies)) {
+            boolean valid = true;
+            for (var entry : cached.files.entrySet()) {
+                check(monitor);
+                if (!entry.getValue().equals(stamp(entry.getKey()))) { valid = false; break; }
+            }
+            if (valid) return cached;
+        }
+        Builder builder = new Builder(monitor);
+        Set<String> units = new HashSet<>(), roots = new LinkedHashSet<>();
+        int visited = 0;
+        for (IPackageFragmentRoot root : project.getAllPackageFragmentRoots()) {
+            check(monitor);
+            if (root.getKind() == IPackageFragmentRoot.K_SOURCE) {
+                if (root.getResource() != null && root.getResource().getLocationURI() != null)
+                    roots.add(root.getResource().getLocationURI().toString());
+                if (root.getJavaProject().getProject().getLocationURI() != null)
+                    roots.add(root.getJavaProject().getProject().getLocationURI().toString());
+                if (root.getResource() != null && root.getResource().getLocation() != null)
+                    builder.metadataDirectory(root.getResource().getLocation().toFile().toPath(), project);
+                for (IJavaElement child : root.getChildren()) {
+                    if (!(child instanceof IPackageFragment pkg)) continue;
+                    for (ICompilationUnit unit : pkg.getCompilationUnits()) {
+                        check(monitor);
+                        unit = copies.getOrDefault(unit.getPrimary().getHandleIdentifier(), unit);
+                        if (!units.add(unit.getHandleIdentifier())) continue;
+                        if (++visited > MAX_UNITS || builder.entries.size() >= MAX_ENTRIES) { builder.incomplete = true; break; }
+                        String source = unit.getSource();
+                        if (source == null) continue;
+                        if (source.length() > MAX_BYTES) { builder.incomplete = true; continue; }
+                        // Cheap lexical filter only chooses candidates; all accepted symbols
+                        // below are verified by JDT bindings, including constants and imports.
+                        if (source.contains("ConfigurationProperties") || source.contains("Value") || source.contains("getProperty") || source.contains("getRequiredProperty"))
+                            builder.parse(unit);
+                    }
+                }
+            } else if (root.isArchive()) {
+                builder.metadata(root, project);
+            }
+        }
+        // Resource roots are not necessarily Java package roots (e.g. Maven resources).
+        // Return project locations as well; the client excludes nested independent modules.
+        roots.add(project.getProject().getLocationURI().toString());
+        builder.metadataDirectory(project.getProject().getLocation().toFile().toPath().resolve("src/main/resources"), project);
+        Index result = new Index(revision, workingCopies, List.copyOf(builder.entries), List.copyOf(roots), Map.copyOf(builder.files), builder.incomplete, builder.parsed);
+        CACHE.remove(id);
+        while (!CACHE.isEmpty() && (CACHE.size() >= 8 ||
+                CACHE.values().stream().mapToInt(value -> value.entries.size()).sum() + result.entries.size() > MAX_ENTRIES))
+            CACHE.remove(CACHE.keySet().iterator().next());
+        CACHE.put(id, result);
+        return result;
+    }
+
+    /** Relaxed matching is reserved for binder/metadata entries. @Value and
+     * Environment lookups retain their literal names; dots remain boundaries. */
+    static boolean matches(String pattern, String key, boolean relaxed) {
+        if (!relaxed) return pattern.equals(key);
+        List<String> a = parts(pattern), b = parts(key);
+        if (a.size() != b.size()) return false;
+        for (int i = 0; i < a.size(); i++) if (!a.get(i).equals("*") && !a.get(i).equals(b.get(i))) return false;
+        return true;
+    }
+    private static List<String> parts(String key) {
+        List<String> result = new ArrayList<>();
+        StringBuilder part = new StringBuilder();
+        for (int i = 0; i < key.length(); i++) {
+            char ch = key.charAt(i);
+            if (ch == '[') {
+                if (!part.isEmpty()) { result.add(canonical(part.toString())); part.setLength(0); }
+                int end = key.indexOf(']', i + 1);
+                if (end < 0) { part.append(key.substring(i)); break; }
+                result.add(canonical(key.substring(i + 1, end))); i = end;
+            } else if (ch == '.') {
+                if (!part.isEmpty() || i == 0 || key.charAt(i - 1) != ']') result.add(canonical(part.toString()));
+                part.setLength(0);
+            } else part.append(ch);
+        }
+        if (!part.isEmpty()) result.add(canonical(part.toString()));
+        return result;
+    }
+    private static String canonical(String key) {
+        return key.replace("-", "").replace("_", "").toLowerCase(Locale.ROOT);
+    }
+
+    private static final class Builder {
+        final IProgressMonitor monitor;
+        final List<Entry> entries = new ArrayList<>();
+        final Map<Path, FileStamp> files = new LinkedHashMap<>();
+        boolean incomplete;
+        int parsed;
+        Builder(IProgressMonitor monitor) { this.monitor = monitor; }
+        void add(String key, IJavaElement element) {
+            if (key.length() > 1024 || entries.size() >= MAX_ENTRIES) { incomplete = true; return; }
+            if (element != null) entries.add(new Entry(key, element.getHandleIdentifier(), null, true));
+        }
+        void use(String key, ICompilationUnit unit, ASTNode node) {
+            if (key.length() > 1024 || entries.size() >= MAX_ENTRIES) { incomplete = true; return; }
+            if (key.isBlank() || key.contains("${") || key.contains("#{")) return;
+            try { entries.add(new Entry(key, "", JDTUtils.toLocation(unit, node.getStartPosition(), node.getLength()), false)); }
+            catch (JavaModelException e) { incomplete = true; }
+        }
+        void parse(ICompilationUnit unit) {
+            check(monitor);
+            ASTParser parser = ASTParser.newParser(AST.getJLSLatest());
+            parser.setSource(unit);
+            parser.setResolveBindings(true);
+            parser.setWorkingCopyOwner(JavaLanguageServerPlugin.getInstance().getWorkingCopyOwner());
+            parser.setBindingsRecovery(false);
+            CompilationUnit tree = (CompilationUnit) parser.createAST(monitor);
+            parsed++;
+            tree.accept(new ASTVisitor() {
+                @Override public void preVisit(ASTNode node) { check(monitor); }
+                @Override public boolean visit(NormalAnnotation node) { annotation(node); return true; }
+                @Override public boolean visit(SingleMemberAnnotation node) { annotation(node); return true; }
+                @Override public boolean visit(MarkerAnnotation node) { annotation(node); return true; }
+                private void annotation(Annotation node) {
+                    IAnnotationBinding binding = node.resolveAnnotationBinding();
+                    if (binding == null) return;
+                    String name = binding.getAnnotationType().getQualifiedName();
+                    if (name.equals(PROPERTIES)) {
+                        String prefix = annotationValue(binding, "prefix");
+                        if (prefix == null || prefix.isEmpty()) prefix = annotationValue(binding, "value");
+                        if (prefix == null) prefix = "";
+                        ASTNode owner = node.getParent();
+                        if (owner instanceof AbstractTypeDeclaration type) {
+                            bind(prefix, type.resolveBinding(), new HashSet<>(), 0);
+                        } else if (owner instanceof MethodDeclaration method && method.resolveBinding() != null) {
+                            add(prefix, method.resolveBinding().getJavaElement());
+                            bind(prefix, method.resolveBinding().getReturnType(), new HashSet<>(), 0);
+                        }
+                    } else if (name.equals(VALUE)) {
+                        String value = annotationValue(binding, "value");
+                        ASTNode expression = node;
+                        if (node instanceof SingleMemberAnnotation single) expression = single.getValue();
+                        else if (node instanceof NormalAnnotation normal) {
+                            for (Object pair : normal.values()) if (pair instanceof MemberValuePair p && p.getName().getIdentifier().equals("value")) expression = p.getValue();
+                        }
+                        if (value != null) placeholders(value, unit, expression);
+                    }
+                }
+                @Override public boolean visit(MethodInvocation node) {
+                    IMethodBinding method = node.resolveMethodBinding();
+                    if (method != null && (method.getName().equals("getProperty") || method.getName().equals("getRequiredProperty")) &&
+                            subtype(method.getDeclaringClass(), RESOLVER, new HashSet<>()) && !node.arguments().isEmpty()) {
+                        Expression arg = (Expression) node.arguments().get(0);
+                        Object constant = arg.resolveConstantExpressionValue();
+                        if (constant instanceof String key) use(key, unit, arg);
+                    }
+                    return true;
+                }
+            });
+        }
+        void placeholders(String text, ICompilationUnit unit, ASTNode node) {
+            // Include nested default placeholders, but never a dynamically composed name.
+            for (int at = text.indexOf("${"); at >= 0; at = text.indexOf("${", at + 2)) {
+                int end = at + 2;
+                while (end < text.length() && text.charAt(end) != ':' && text.charAt(end) != '}') end++;
+                if (end < text.length()) use(text.substring(at + 2, end), unit, node);
+            }
+        }
+        void bind(String prefix, ITypeBinding type, Set<String> visiting, int depth) {
+            check(monitor);
+            if (type == null || type.isRecovered() || type.isPrimitive() || type.isEnum()) return;
+            String qualified = type.getErasure().getQualifiedName();
+            if (qualified.startsWith("java.") || qualified.startsWith("javax.")) return;
+            if (depth > 12 || !visiting.add(type.getKey())) return;
+            try {
+                if (!prefix.isEmpty()) add(prefix, type.getJavaElement());
+                List<IMethodBinding> constructors = Arrays.stream(type.getDeclaredMethods())
+                    .filter(m -> m.isConstructor() && !Modifier.isPrivate(m.getModifiers())).toList();
+                for (IMethodBinding constructor : constructors) {
+                    boolean explicit = Arrays.stream(constructor.getAnnotations()).anyMatch(a ->
+                        a.getAnnotationType().getQualifiedName().equals("org.springframework.boot.context.properties.bind.ConstructorBinding") ||
+                        a.getAnnotationType().getQualifiedName().equals("org.springframework.boot.context.properties.ConstructorBinding"));
+                    if (!explicit && constructors.size() != 1) continue;
+                    String[] parameters = constructor.getParameterNames();
+                    for (int i = 0; i < parameters.length; i++) {
+                        String name = parameters[i];
+                        for (IAnnotationBinding annotation : constructor.getParameterAnnotations(i)) {
+                            if (annotation.getAnnotationType().getQualifiedName().equals("org.springframework.boot.context.properties.bind.Name")) {
+                                String alias = annotationValue(annotation, "value");
+                                if (alias != null) name = alias;
+                            }
+                        }
+                        // Prefer fields/accessors for ordinary parameters; aliases and
+                        // constructor-only properties still have a navigable declaration.
+                        final String parameterName = name;
+                        if (Arrays.stream(type.getDeclaredFields()).noneMatch(f -> f.getName().equals(parameterName))) {
+                            add(join(prefix, name), constructor.getJavaElement());
+                            nested(join(prefix, name), constructor.getParameterTypes()[i], constructor.getJavaElement(), visiting, depth + 1);
+                        }
+                    }
+                }
+                Set<String> names = new HashSet<>();
+                for (ITypeBinding current = type; current != null && !current.getQualifiedName().equals("java.lang.Object"); current = current.getSuperclass()) {
+                    for (IVariableBinding field : current.getDeclaredFields()) {
+                        if (Modifier.isStatic(field.getModifiers()) || field.isSynthetic() || !names.add(field.getName())) continue;
+                        String key = join(prefix, field.getName());
+                        add(key, field.getJavaElement());
+                        nested(key, field.getType(), field.getJavaElement(), visiting, depth + 1);
+                    }
+                    for (IMethodBinding method : current.getDeclaredMethods()) {
+                        if (Modifier.isStatic(method.getModifiers()) || method.isConstructor()) continue;
+                        String name = method.getName();
+                        String property = null;
+                        ITypeBinding propertyType = null;
+                        if (name.startsWith("set") && name.length() > 3 && method.getParameterTypes().length == 1) {
+                            property = name.substring(3); propertyType = method.getParameterTypes()[0];
+                        } else if (name.startsWith("get") && name.length() > 3 && method.getParameterTypes().length == 0) {
+                            property = name.substring(3); propertyType = method.getReturnType();
+                        }
+                        if (property != null) {
+                            property = Character.toLowerCase(property.charAt(0)) + property.substring(1);
+                            String key = join(prefix, property);
+                            add(key, method.getJavaElement());
+                            if (names.add(property)) nested(key, propertyType, method.getJavaElement(), visiting, depth + 1);
+                        }
+                    }
+                }
+            } finally { visiting.remove(type.getKey()); }
+        }
+        void nested(String key, ITypeBinding type, IJavaElement owner, Set<String> visiting, int depth) {
+            if (type == null) return;
+            if (type.isArray()) { add(key + "[*]", owner); bind(key + "[*]", type.getElementType(), visiting, depth); return; }
+            String raw = type.getErasure().getQualifiedName();
+            if (subtype(type, "java.util.Map", new HashSet<>())) {
+                add(key + ".*", owner);
+                var args = type.getTypeArguments();
+                if (args.length == 2) bind(key + ".*", args[1], visiting, depth);
+            } else if (subtype(type, "java.util.Collection", new HashSet<>())) {
+                add(key + "[*]", owner);
+                var args = type.getTypeArguments();
+                if (args.length == 1) bind(key + "[*]", args[0], visiting, depth);
+            } else if (!type.isPrimitive() && !type.isEnum() && !raw.startsWith("java.") && !raw.startsWith("javax.")) {
+                bind(key, type, visiting, depth);
+            }
+        }
+        void metadata(IPackageFragmentRoot root, IJavaProject project) {
+            check(monitor);
+            Path path = root.getPath().toFile().toPath();
+            if (!root.isExternal() && root.getResource() != null && root.getResource().getLocation() != null)
+                path = root.getResource().getLocation().toFile().toPath();
+            files.put(path, stamp(path));
+            if (!Files.isRegularFile(path)) return;
+            try (ZipFile zip = new ZipFile(path.toFile())) {
+                for (String filename : List.of("spring-configuration-metadata.json", "additional-spring-configuration-metadata.json")) {
+                    var entry = zip.getEntry("META-INF/" + filename);
+                    if (entry == null) continue;
+                    if (entry.getSize() > MAX_BYTES) { incomplete = true; continue; }
+                    JsonObject metadata;
+                    try (var stream = zip.getInputStream(entry)) {
+                        byte[] bytes = stream.readNBytes(MAX_BYTES + 1);
+                        if (bytes.length > MAX_BYTES) { incomplete = true; continue; }
+                        metadata = JsonParser.parseString(new String(bytes, java.nio.charset.StandardCharsets.UTF_8)).getAsJsonObject();
+                    }
+                    metadataObject(metadata, project);
+                }
+            } catch (Exception e) { if (e instanceof OperationCanceledException) throw (OperationCanceledException)e; incomplete = true; }
+        }
+        void metadataObject(JsonObject metadata, IJavaProject project) throws JavaModelException {
+            JsonArray groups = metadata.has("groups") ? metadata.getAsJsonArray("groups") : new JsonArray();
+            for (JsonElement value : groups) {
+                check(monitor);
+                JsonObject group = value.getAsJsonObject();
+                String name = string(group, "name"), source = string(group, "sourceType");
+                if (source == null) source = string(group, "type");
+                if (name != null && source != null) add(name, project.findType(source.replace('$', '.'), monitor));
+            }
+            if (!metadata.has("properties")) return;
+            for (JsonElement value : metadata.getAsJsonArray("properties")) {
+                check(monitor);
+                if (entries.size() >= MAX_ENTRIES) { incomplete = true; return; }
+                JsonObject property = value.getAsJsonObject();
+                String key = string(property, "name"), source = string(property, "sourceType"), prefix = "";
+                if (key == null) continue;
+                JsonObject owner = null;
+                for (JsonElement groupValue : groups) {
+                    JsonObject group = groupValue.getAsJsonObject();
+                    String name = string(group, "name");
+                    if (name != null && key.startsWith(name + ".") && name.length() > prefix.length()) {
+                        prefix = name; owner = group;
+                    }
+                }
+                if (source == null && owner != null) source = string(owner, "type");
+                if (source == null && owner != null) source = string(owner, "sourceType");
+                if (source == null) continue;
+                IType type = project.findType(source.replace('$', '.'), monitor);
+                if (type == null) continue;
+                String leaf = key.substring(prefix.isEmpty() ? 0 : prefix.length() + 1);
+                IJavaElement target = member(type, leaf, new HashSet<>());
+                if (target == null && owner != null && string(owner, "sourceMethod") != null) {
+                    String declaring = string(owner, "sourceType");
+                    IType factory = declaring == null ? null : project.findType(declaring.replace('$', '.'), monitor);
+                    if (factory != null) {
+                        String methodName = string(owner, "sourceMethod").split("\\(", 2)[0];
+                        for (IMethod method : factory.getMethods()) if (method.getElementName().equals(methodName)) { target = method; break; }
+                    }
+                }
+                add(key, target == null ? type : target);
+            }
+        }
+        void metadataDirectory(Path directory, IJavaProject project) {
+            for (String name : List.of("spring-configuration-metadata.json", "additional-spring-configuration-metadata.json")) {
+                Path file = directory.resolve("META-INF").resolve(name);
+                files.put(file, stamp(file));
+                if (!Files.isRegularFile(file)) continue;
+                try {
+                    if (Files.size(file) > MAX_BYTES) { incomplete = true; continue; }
+                    try (var stream = Files.newInputStream(file)) {
+                        byte[] bytes = stream.readNBytes(MAX_BYTES + 1);
+                        if (bytes.length > MAX_BYTES) { incomplete = true; continue; }
+                        metadataObject(JsonParser.parseString(new String(bytes, java.nio.charset.StandardCharsets.UTF_8)).getAsJsonObject(), project);
+                    }
+                } catch (Exception e) { if (e instanceof OperationCanceledException) throw (OperationCanceledException)e; incomplete = true; }
+            }
+        }
+    }
+    private static IJavaElement member(IType type, String key, Set<String> seen) throws JavaModelException {
+        if (type == null || !seen.add(type.getHandleIdentifier())) return null;
+        String part = key.split("\\.", 2)[0];
+        for (IField field : type.getFields()) if (canonical(field.getElementName()).equals(canonical(part))) {
+            if (!key.contains(".")) return field;
+            String signature = Signature.toString(Signature.getTypeErasure(field.getTypeSignature()));
+            String[][] resolved = type.resolveType(signature);
+            IType nested = type.getJavaProject().findType(signature);
+            if (nested == null && resolved != null && resolved.length == 1)
+                nested = type.getJavaProject().findType(resolved[0][0] + "." + resolved[0][1]);
+            IJavaElement found = member(nested, key.substring(key.indexOf('.') + 1), seen);
+            return found == null ? field : found;
+        }
+        for (IMethod method : type.getMethods()) {
+            String name = method.getElementName();
+            if (name.length() > 3 && (name.startsWith("get") || name.startsWith("set")) && canonical(name.substring(3)).equals(canonical(part))) return method;
+        }
+        String parent = type.getSuperclassName();
+        if (parent != null) {
+            String[][] resolved = type.resolveType(parent);
+            if (resolved != null && resolved.length == 1)
+                return member(type.getJavaProject().findType(resolved[0][0] + "." + resolved[0][1]), key, seen);
+        }
+        return null;
+    }
+    private static String string(JsonObject object, String key) {
+        return object.has(key) && object.get(key).isJsonPrimitive() ? object.get(key).getAsString() : null;
+    }
+    private static String annotationValue(IAnnotationBinding binding, String name) {
+        for (IMemberValuePairBinding pair : binding.getAllMemberValuePairs())
+            if (pair.getName().equals(name) && pair.getValue() instanceof String s) return s;
+        return null;
+    }
+    private static String join(String prefix, String name) { return prefix.isEmpty() ? name : prefix + "." + name; }
+    private static boolean subtype(ITypeBinding type, String name, Set<String> seen) {
+        if (type == null || !seen.add(type.getKey())) return false;
+        if (type.getErasure().getQualifiedName().equals(name)) return true;
+        for (ITypeBinding face : type.getInterfaces()) if (subtype(face, name, seen)) return true;
+        return subtype(type.getSuperclass(), name, seen);
+    }
+}
diff --git a/plugins/java-usages/tests/configuration.py b/plugins/java-usages/tests/configuration.py
new file mode 100644
index 000000000..9a42f4a0d
--- /dev/null
+++ b/plugins/java-usages/tests/configuration.py
@@ -0,0 +1,220 @@
+"""Real JDT LS configuration-navigation regression and warm-query benchmark.
+Run with Java 25 on PATH: python3 configuration.py /path/to/jdtls
+Fixtures use small Spring API stubs; no Maven/network/build of a user's project.
+"""
+import os
+import json
+import pathlib
+import platform
+import queue
+import subprocess
+import sys
+import tempfile
+import threading
+import time
+import zipfile
+
+home = pathlib.Path(sys.argv[1]).resolve()
+bundle = pathlib.Path(__file__).resolve().parents[1] / 'openidea-java-usages.jar'
+work = pathlib.Path(tempfile.mkdtemp(prefix='openidea-configuration-'))
+project = work / 'project'
+source_dir = project / 'src'
+source_dir.mkdir(parents=True)
+
+def write(relative, text):
+    file = source_dir / relative
+    file.parent.mkdir(parents=True, exist_ok=True)
+    file.write_text(text)
+    return file
+
+write('org/springframework/boot/context/properties/ConfigurationProperties.java', '''package org.springframework.boot.context.properties;
+public @interface ConfigurationProperties { String value() default ""; String prefix() default ""; }''')
+write('org/springframework/boot/context/properties/bind/Name.java', 'package org.springframework.boot.context.properties.bind; public @interface Name { String value(); }')
+write('org/springframework/beans/factory/annotation/Value.java', '''package org.springframework.beans.factory.annotation;
+public @interface Value { String value(); }''')
+write('org/springframework/core/env/PropertyResolver.java', '''package org.springframework.core.env;
+public interface PropertyResolver { String getProperty(String key); String getRequiredProperty(String key); }''')
+write('org/springframework/core/env/Environment.java', '''package org.springframework.core.env;
+public interface Environment extends PropertyResolver {}''')
+source = '''package demo;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.core.env.Environment;
+@ConfigurationProperties(prefix="app")
+class Settings extends Parent {
+    int timeOut;
+    Nested nested;
+    java.util.List<Nested> clients;
+    java.util.Map<String, Nested> routes;
+    java.util.List<String> tags;
+    java.util.Map<String, String> labels;
+    public int getTimeOut() { return timeOut; }
+    public void setTimeOut(int value) { timeOut = value; }
+}
+class Parent { boolean enabled; }
+class Nested { String url; }
+@ConfigurationProperties("record")
+record RecordSettings(String name, int count) {}
+@ConfigurationProperties("constructor")
+class ConstructorSettings {
+    ConstructorSettings(@org.springframework.boot.context.properties.bind.Name("remote-name") String name) {}
+}
+class Consumers {
+    static final String KEY = "app.time-out";
+    @Value("${app.time-out:30}") String timeout;
+    @Value("${app.missing:${app.backup:42}}") String fallback;
+    String call(Environment env) { return env.getProperty(KEY); }
+    String required(Environment env) { return env.getRequiredProperty("app.required"); }
+    String dynamic(Environment env, String key) { return env.getProperty(key); }
+    String unrelated(Fake env) { return env.getProperty("app.time-out"); }
+    @ConfigurationProperties("bean") Nested bean() { return new Nested(); }
+}
+class Fake { String getProperty(String name) { return name; } }
+'''
+file = write('demo/Settings.java', source)
+if os.environ.get('OPENIDEA_CONFIGURATION_STRESS') == '1':
+    for i in range(3000):
+        write(f'noise/Plain{i}.java', f'package noise; class Plain{i} {{ int number; }}')
+    for i in range(100):
+        write(f'noise/Config{i}.java', f'package noise; @org.springframework.boot.context.properties.ConfigurationProperties(prefix="stress{i}") class Config{i} {{ int value; }}')
+write('demo/NotSpring.java', '''package demo;
+@interface ConfigurationProperties { String prefix(); }
+@ConfigurationProperties(prefix="fake") class NotSpring { int timeOut; }
+''')
+local_metadata = project / 'src/main/resources/META-INF'
+local_metadata.mkdir(parents=True)
+(local_metadata / 'additional-spring-configuration-metadata.json').write_text(json.dumps({
+    'groups': [{'name': 'extra', 'sourceType': 'demo.Nested', 'type': 'demo.Nested'}],
+    'properties': [{'name': 'extra.url', 'sourceType': 'demo.Nested'}]
+}))
+# A dependency with metadata and attached source exercises actual library locations.
+libsource = work / 'libsrc/vendor/LibrarySettings.java'
+libsource.parent.mkdir(parents=True)
+libsource.write_text('package vendor; public class LibrarySettings { public int port; public int getPort() { return port; } }')
+classes = work / 'libclasses'
+classes.mkdir()
+subprocess.run(['javac', '--release', '21', '-d', str(classes), str(libsource)], check=True)
+library = work / 'library.jar'
+metadata = {'groups': [{'name': 'vendor', 'type': 'vendor.LibrarySettings', 'sourceType': 'vendor.LibrarySettings'}],
+            'properties': [{'name': 'vendor.port', 'type': 'java.lang.Integer', 'sourceType': 'vendor.LibrarySettings'}]}
+with zipfile.ZipFile(library, 'w') as z:
+    z.write(classes / 'vendor/LibrarySettings.class', 'vendor/LibrarySettings.class')
+    z.writestr('META-INF/spring-configuration-metadata.json', json.dumps(metadata))
+sourcejar = work / 'library-sources.jar'
+with zipfile.ZipFile(sourcejar, 'w') as z:
+    z.write(libsource, 'vendor/LibrarySettings.java')
+(project / '.project').write_text('<projectDescription><name>configuration</name><buildSpec><buildCommand><name>org.eclipse.jdt.core.javabuilder</name></buildCommand></buildSpec><natures><nature>org.eclipse.jdt.core.javanature</nature></natures></projectDescription>')
+spring_jar = os.environ.get('OPENIDEA_SPRING_BOOT_JAR')
+extra_classpath = f'<classpathentry kind="lib" path="{pathlib.Path(spring_jar).resolve()}"/>' if spring_jar else ''
+(project / '.classpath').write_text(f'<classpath><classpathentry kind="src" path="src"/><classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/><classpathentry kind="lib" path="{library}" sourcepath="{sourcejar}"/>{extra_classpath}<classpathentry kind="output" path="bin"/></classpath>')
+config = work / 'config'
+config.mkdir()
+name = {'Darwin': 'config_mac', 'Windows': 'config_win'}.get(platform.system(), 'config_linux')
+names = ([name + '_arm'] if platform.machine().lower() in ('arm64', 'aarch64') else []) + [name]
+(config / 'config.ini').write_bytes(next(home / n / 'config.ini' for n in names if (home / n / 'config.ini').exists()).read_bytes())
+log = (work / 'stderr.log').open('w')
+proc = subprocess.Popen(['java', '-Declipse.application=org.eclipse.jdt.ls.core.id1', '-Dosgi.bundles.defaultStartLevel=4', '-Declipse.product=org.eclipse.jdt.ls.core.product', '-Xmx1G', '--add-modules=ALL-SYSTEM', '--add-opens', 'java.base/java.util=ALL-UNNAMED', '--add-opens', 'java.base/java.lang=ALL-UNNAMED', '-jar', str(next((home / 'plugins').glob('org.eclipse.equinox.launcher_*.jar'))), '-configuration', str(config), '-data', str(work / 'metadata')], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=log)
+messages = queue.Queue()
+lock = threading.Lock()
+def send(message):
+    data = json.dumps(message).encode()
+    with lock:
+        proc.stdin.write(f'Content-Length: {len(data)}\r\n\r\n'.encode() + data)
+        proc.stdin.flush()
+def read():
+    while True:
+        headers = {}
+        while True:
+            line = proc.stdout.readline()
+            if not line: return
+            if line == b'\r\n': break
+            k, v = line.decode().split(':', 1)
+            headers[k.lower()] = v.strip()
+        message = json.loads(proc.stdout.read(int(headers['content-length'])))
+        if 'method' in message and 'id' in message:
+            send({'jsonrpc': '2.0', 'id': message['id'], 'result': [] if message['method'] == 'workspace/configuration' else None})
+        else: messages.put(message)
+threading.Thread(target=read, daemon=True).start()
+sequence = 0
+transcript = []
+def request(method, params):
+    global sequence
+    sequence += 1
+    send({'jsonrpc': '2.0', 'id': sequence, 'method': method, 'params': params})
+    deadline = time.monotonic() + 180
+    while time.monotonic() < deadline:
+        msg = messages.get(timeout=max(1, deadline - time.monotonic()))
+        transcript.append(msg)
+        if msg.get('id') == sequence:
+            if 'error' in msg: raise RuntimeError(msg['error'])
+            return msg.get('result')
+    raise TimeoutError(method)
+def query(key, uri=None, line=0, col=0):
+    return request('workspace/executeCommand', {'command': 'openidea.java.configuration', 'arguments': [uri or (project / 'application.yml').as_uri(), key, line, col, key is None, False]})
+def names(result):
+    return {p['name'] for p in result['keys']}
+try:
+    init = request('initialize', {'processId': None, 'rootUri': project.as_uri(), 'workspaceFolders': [{'uri': project.as_uri(), 'name': 'configuration'}], 'capabilities': {'textDocument': {'definition': {'linkSupport': False}}}, 'initializationOptions': {'bundles': [str(bundle)], 'extendedClientCapabilities': {'classFileContentsSupport': True}, 'settings': {'java': {'import': {'gradle': {'enabled': False}, 'maven': {'enabled': False}}}}}})
+    send({'jsonrpc': '2.0', 'method': 'initialized', 'params': {}})
+    send({'jsonrpc': '2.0', 'method': 'textDocument/didOpen', 'params': {'textDocument': {'uri': file.as_uri(), 'languageId': 'java', 'version': 1, 'text': source}}})
+    request('java/buildWorkspace', True)
+    assert 'openidea.java.configuration' in init['capabilities']['executeCommandProvider']['commands'], init
+    results = {}
+    for key in ['app', 'vendor', 'app.time-out', 'app.enabled', 'app.nested.url', 'app.clients[0].url', 'app.routes.east.url', 'app.tags[0]', 'app.labels.region', 'app.labels[region.name]', 'constructor.remote-name', 'record.name', 'bean.url', 'app.backup', 'app.required', 'vendor.port', 'extra.url']:
+        start = time.perf_counter()
+        result = query(key)
+        results[key] = {'seconds': time.perf_counter() - start, 'response': result}
+        assert result['locations'], (key, result)
+    attached = request('java/classFileContents', {'uri': results['vendor.port']['response']['locations'][0]['uri']})
+    assert attached and 'LibrarySettings' in attached and 'port' in attached, attached
+    if spring_jar:
+        for key in ['server.port', 'spring.datasource.url', 'spring.jackson.date-format']:
+            result = query(key)
+            assert result['locations'], (key, result)
+            assert all(loc['uri'].startswith('jdt://') for loc in result['locations']), result
+            results[key] = {'response': result}
+            if key == 'server.port':
+                decompiled = request('java/classFileContents', {'uri': result['locations'][0]['uri']})
+                assert decompiled and 'ServerProperties' in decompiled and 'port' in decompiled, decompiled
+    assert not query('app.tags[0].value')['locations']
+    assert not query('app.labels.region.coder')['locations']
+    assert not query('fake.time-out')['locations']
+    assert not query('app.does-not-exist')['locations']
+    metadata_file = local_metadata / 'additional-spring-configuration-metadata.json'
+    metadata_file.write_text(metadata_file.read_text().replace('extra', 'newer'))
+    assert query('newer.url')['locations']
+    assert not query('extra.url')['locations']
+    # Property references include member usages and consumers, without declarations.
+    references = request('workspace/executeCommand', {'command': 'openidea.java.configuration',
+        'arguments': [(project / 'application.yml').as_uri(), 'app.time-out', 0, 0, True, False]})
+    assert references['locations'], references
+    assert any(loc['range']['start']['line'] == next(i for i, line in enumerate(source.splitlines()) if 'getProperty(KEY)' in line) for loc in references['locations']), references
+    # 3 binding targets + @Value + Environment constant; Fake.getProperty excluded.
+    timeout = query('app.time-out')
+    assert len(timeout['locations']) == 5, timeout
+    for needle, expected in [('int timeOut;', 'app.timeOut'), ('"${app.time-out:30}"', 'app.time-out'), ('env.getProperty(KEY)', 'app.time-out')]:
+        line, text = next((i, s) for i, s in enumerate(source.splitlines()) if needle in s)
+        col = text.index(needle) + (4 if needle == 'int timeOut;' else (len('env.getProperty(') if needle.startswith('env.') else 4))
+        reverse = query(None, file.as_uri(), line, col)
+        assert expected in names(reverse), (needle, reverse)
+    warm = []
+    for _ in range(20):
+        start = time.perf_counter(); query('app.time-out'); warm.append(time.perf_counter() - start)
+    # Unsaved changes must replace old keys, and closing must restore disk keys.
+    changed = source.replace('prefix="app"', 'prefix="edited"').replace('${app.time-out:30}', '${edited.timeout:30}')
+    send({'jsonrpc': '2.0', 'method': 'textDocument/didChange', 'params': {'textDocument': {'uri': file.as_uri(), 'version': 2}, 'contentChanges': [{'text': changed}]}})
+    edit_start = time.perf_counter()
+    updated = query('edited.time-out')
+    edit_ms = (time.perf_counter() - edit_start) * 1000
+    assert updated['locations'], updated
+    assert not query('app.nested.url')['locations']
+    send({'jsonrpc': '2.0', 'method': 'textDocument/didClose', 'params': {'textDocument': {'uri': file.as_uri()}}})
+    restored = query('app.nested.url')
+    assert restored['locations'], restored
+    evidence = {'stress': os.environ.get('OPENIDEA_CONFIGURATION_STRESS') == '1', 'editRebuildMs': edit_ms, 'cases': results, 'warmMedianMs': sorted(warm)[len(warm)//2] * 1000, 'warmMaxMs': max(warm) * 1000}
+    (work / 'evidence.json').write_text(json.dumps(evidence, indent=2))
+    print(json.dumps(evidence, indent=2))
+finally:
+    (work / 'transcript.json').write_text(json.dumps(transcript, indent=2))
+    proc.terminate(); proc.wait(timeout=20)
+    print('Evidence:', work, file=sys.stderr)