initial re-work of async behavior of language server, looking at the text document service first

headless-services/bosh-language-server/src/main/java/org/springframework/ide/vscode/bosh/BoshDefintionFinder.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -75,8 +75,9 @@ public class BoshDefintionFinder extends SimpleDefinitionFinder {
 	@Override
 	public List<LocationLink> handle(DefinitionParams params) {
 		try {
-			TextDocument doc = server.getTextDocumentService().get(params.getTextDocument().getUri());
-			if (doc!=null) {
+			TextDocument doc = server.getTextDocumentService().getLatestSnapshot(params);
+
+			if (doc != null) {
 				YamlFileAST ast = asts.getSafeAst(doc, false);
 				if (ast!=null) {
 					Node refNode = ast.findNode(doc.toOffset(params.getPosition()));

headless-services/commons/commons-language-server/src/main/java/org/springframework/ide/vscode/commons/languageserver/completion/VscodeCompletionEngineAdapter.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016, 2019 Pivotal, Inc.
+ * Copyright (c) 2016, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -128,8 +128,10 @@ public class VscodeCompletionEngineAdapter implements VscodeCompletionEngine {
 
 	private Mono<CompletionList> getCompletionsMono(TextDocumentPositionParams params) {
 		SimpleTextDocumentService documents = server.getTextDocumentService();
-		if (documents.get(params) != null) {
-			TextDocument doc = documents.getDocumentSnapshot(params.getTextDocument());
+		
+		TextDocument doc = documents.getLatestSnapshot(params);
+		if (doc != null) {
+
 			return Mono.fromCallable(() -> {
 				log.info("Starting completion handling");
 				if (resolver!=null) {

headless-services/commons/commons-language-server/src/main/java/org/springframework/ide/vscode/commons/languageserver/composable/CompositeLanguageServerComponents.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2018, 2020 Pivotal, Inc.
+ * Copyright (c) 2018, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -11,9 +11,7 @@
 package org.springframework.ide.vscode.commons.languageserver.composable;
 
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.Optional;
 import java.util.Set;
 
@@ -21,8 +19,6 @@ import org.eclipse.lsp4j.Hover;
 import org.eclipse.lsp4j.HoverParams;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.springframework.ide.vscode.commons.languageserver.completion.CompositeCompletionEngine;
-import org.springframework.ide.vscode.commons.languageserver.completion.ICompletionEngine;
 import org.springframework.ide.vscode.commons.languageserver.reconcile.IProblemCollector;
 import org.springframework.ide.vscode.commons.languageserver.reconcile.IReconcileEngine;
 import org.springframework.ide.vscode.commons.languageserver.util.HoverHandler;
@@ -86,7 +82,7 @@ public class CompositeLanguageServerComponents implements LanguageServerComponen
 		this.hoverHandler = new HoverHandler() {
 			@Override
 			public Hover handle(HoverParams params) {
-				TextDocument doc = server.getTextDocumentService().get(params.getTextDocument().getUri());
+				TextDocument doc = server.getTextDocumentService().getLatestSnapshot(params.getTextDocument().getUri());
 				LanguageId language = doc.getLanguageId();
 				LanguageServerComponents subComponents = componentsByLanguageId.get(language);
 				if (subComponents!=null) {

headless-services/commons/commons-language-server/src/main/java/org/springframework/ide/vscode/commons/languageserver/definition/SimpleDefinitionFinder.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -41,7 +41,8 @@ public class SimpleDefinitionFinder implements DefinitionHandler {
 	@Override
 	public List<LocationLink> handle(DefinitionParams params) {
 		try {
-			TextDocument doc = server.getTextDocumentService().get(params.getTextDocument().getUri());
+			TextDocument doc = server.getTextDocumentService().getLatestSnapshot(params.getTextDocument().getUri());
+
 			if (doc != null) {
 				int offset = doc.toOffset(params.getPosition());
 				int start = offset;

headless-services/commons/commons-language-server/src/main/java/org/springframework/ide/vscode/commons/languageserver/hover/VscodeHoverEngineAdapter.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016, 2020 Pivotal, Inc.
+ * Copyright (c) 2016, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -60,7 +60,8 @@ public class VscodeHoverEngineAdapter implements HoverHandler {
 	public Hover handle(HoverParams params) {
 		try {
 			SimpleTextDocumentService documents = server.getTextDocumentService();
-			TextDocument doc = documents.get(params.getTextDocument().getUri());
+			TextDocument doc = documents.getLatestSnapshot(params.getTextDocument().getUri());
+
 			if (doc != null) {
 				int offset = doc.toOffset(params.getPosition());
 

headless-services/commons/commons-language-server/src/main/java/org/springframework/ide/vscode/commons/languageserver/util/SimpleLanguageServer.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016, 2020 Pivotal, Inc.
+ * Copyright (c) 2016, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -534,13 +534,13 @@ public final class SimpleLanguageServer implements Sts4LanguageServer, LanguageC
 	public void validateWith(TextDocumentIdentifier docId, IReconcileEngine engine) {
 		SimpleTextDocumentService documents = getTextDocumentService();
 
-		TextDocument document = documents.getDocument(docId.getUri());
-		if (document == null) {
+		TextDocument doc = documents.getLatestSnapshot(docId.getUri());
+		if (doc == null) {
 			log.debug("Reconcile skipped due to document doesn't exist anymore {}", docId.getUri());
 			return;
 		}
 		
-		int requestedVersion = document.getVersion();
+		int requestedVersion = doc.getVersion();
 		VersionedTextDocumentIdentifier request = new VersionedTextDocumentIdentifier(docId.getUri(), requestedVersion);
 		log.debug("Reconcile requested {} - {}", request.getUri(), request.getVersion());
 		if (!queuedReconcileRequests.add(request)) {
@@ -557,13 +557,13 @@ public final class SimpleLanguageServer implements Sts4LanguageServer, LanguageC
 			queuedReconcileRequests.remove(request);
 			log.debug("Reconcile starting {} - {}", request.getUri(), request.getVersion());
 
-			TextDocument doc = documents.getDocument(docId.getUri()).copy();
+//			TextDocument doc = documents.getDocument(docId.getUri()).copy();
 
-			if (doc == null) {
-				log.debug("Reconcile aborted due to document doesn't exist {} - {}", request.getUri(), request.getVersion());
-				//Do not bother reconciling if document doesn't exist anymore (got closed in the meantime)
-				return;
-			}
+//			if (doc == null) {
+//				log.debug("Reconcile aborted due to document doesn't exist {} - {}", request.getUri(), request.getVersion());
+//				//Do not bother reconciling if document doesn't exist anymore (got closed in the meantime)
+//				return;
+//			}
 
 			if (requestedVersion != doc.getVersion()) {
 				log.debug("Reconcile aborted due to document being already stale {} - {}", request.getUri(), request.getVersion());

headless-services/commons/commons-language-server/src/main/java/org/springframework/ide/vscode/commons/languageserver/util/SimpleTextDocumentService.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016, 2020 Pivotal, Inc.
+ * Copyright (c) 2016, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -10,13 +10,12 @@
  *******************************************************************************/
 package org.springframework.ide.vscode.commons.languageserver.util;
 
-import java.time.Duration;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
@@ -46,7 +45,6 @@ import org.eclipse.lsp4j.HoverParams;
 import org.eclipse.lsp4j.Location;
 import org.eclipse.lsp4j.LocationLink;
 import org.eclipse.lsp4j.PublishDiagnosticsParams;
-import org.eclipse.lsp4j.Range;
 import org.eclipse.lsp4j.ReferenceParams;
 import org.eclipse.lsp4j.RenameParams;
 import org.eclipse.lsp4j.SignatureHelp;
@@ -59,6 +57,7 @@ import org.eclipse.lsp4j.TextDocumentPositionParams;
 import org.eclipse.lsp4j.TextEdit;
 import org.eclipse.lsp4j.VersionedTextDocumentIdentifier;
 import org.eclipse.lsp4j.WorkspaceEdit;
+import org.eclipse.lsp4j.jsonrpc.CompletableFutures;
 import org.eclipse.lsp4j.jsonrpc.messages.Either;
 import org.eclipse.lsp4j.services.LanguageClient;
 import org.eclipse.lsp4j.services.TextDocumentService;
@@ -67,182 +66,132 @@ import org.slf4j.LoggerFactory;
 import org.springframework.ide.vscode.commons.languageserver.config.LanguageServerProperties;
 import org.springframework.ide.vscode.commons.languageserver.quickfix.Quickfix;
 import org.springframework.ide.vscode.commons.util.Assert;
-import org.springframework.ide.vscode.commons.util.AsyncRunner;
 import org.springframework.ide.vscode.commons.util.BadLocationException;
 import org.springframework.ide.vscode.commons.util.CollectorUtil;
-import org.springframework.ide.vscode.commons.util.ExceptionUtil;
 import org.springframework.ide.vscode.commons.util.text.LanguageId;
 import org.springframework.ide.vscode.commons.util.text.TextDocument;
 
 import com.google.common.collect.ImmutableList;
 
-import reactor.core.publisher.Mono;
-
 public class SimpleTextDocumentService implements TextDocumentService, DocumentEventListenerManager {
 
 	private static Logger log = LoggerFactory.getLogger(SimpleTextDocumentService.class);
 	
-	final private SimpleLanguageServer server;
-	final private LanguageServerProperties props;
-	private Map<String, TrackedDocument> documents = new HashMap<>();
-	private ListenerList<TextDocumentContentChange> documentChangeListeners = new ListenerList<>();
-	private ListenerList<TextDocument> documentCloseListeners = new ListenerList<>();
-	private ListenerList<TextDocument> documentOpenListeners = new ListenerList<>();
+	private final SimpleLanguageServer server;
+	private final LanguageServerProperties props;
+	
+	private final ConcurrentMap<String, TrackedDocument> documents = new ConcurrentHashMap<>();
+	private final ConcurrentMap<String, TextDocument> documentSnapshots = new ConcurrentHashMap<>();
 
-	private CompletionHandler completionHandler = null;
-	private CompletionResolveHandler completionResolveHandler = null;
+	private final ListenerList<TextDocumentContentChange> documentChangeListeners = new ListenerList<>();
+	private final ListenerList<TextDocument> documentCloseListeners = new ListenerList<>();
+	private final ListenerList<TextDocument> documentOpenListeners = new ListenerList<>();
+	private List<Consumer<TextDocumentSaveChange>> documentSaveListeners = ImmutableList.of();
 
-	private HoverHandler hoverHandler = null;
+	private CompletionHandler completionHandler;
+	private CompletionResolveHandler completionResolveHandler;
+	private HoverHandler hoverHandler;
 	private DefinitionHandler definitionHandler;
 	private ReferencesHandler referencesHandler;
-
 	private DocumentSymbolHandler documentSymbolHandler;
 	private DocumentHighlightHandler documentHighlightHandler;
-
 	private CodeLensHandler codeLensHandler;
 	private CodeLensResolveHandler codeLensResolveHandler;
 
-	private List<Consumer<TextDocumentSaveChange>> documentSaveListeners = ImmutableList.of();
-	private AsyncRunner async;
-
-
 	public SimpleTextDocumentService(SimpleLanguageServer server, LanguageServerProperties props) {
 		this.server = server;
 		this.props = props;
-		this.async = server.getAsync();
-	}
-
-	public synchronized void onHover(HoverHandler h) {
-		Assert.isNull("A hover handler is already set, multiple handlers not supported yet", hoverHandler);
-		this.hoverHandler = h;
-	}
-
-	public synchronized void onCodeLens(CodeLensHandler h) {
-		Assert.isNull("A code lens handler is already set, multiple handlers not supported yet", codeLensHandler);
-		this.codeLensHandler = h;
-	}
-
-	public synchronized void onCodeLensResolve(CodeLensResolveHandler h) {
-		Assert.isNull("A code lens resolve handler is already set, multiple handlers not supported yet", codeLensResolveHandler);
-		this.codeLensResolveHandler = h;
-	}
-
-	public synchronized void onDocumentSymbol(DocumentSymbolHandler h) {
-		Assert.isNull("A DocumentSymbolHandler is already set, multiple handlers not supported yet", documentSymbolHandler);
-		this.documentSymbolHandler = h;
-	}
-
-	public synchronized void onDocumentHighlight(DocumentHighlightHandler h) {
-		Assert.isNull("A DocumentHighlightHandler is already set, multiple handlers not supported yet", documentHighlightHandler);
-		this.documentHighlightHandler = h;
-	}
-
-	 public synchronized void onCompletion(CompletionHandler h) {
-		Assert.isNull("A completion handler is already set, multiple handlers not supported yet", completionHandler);
-		this.completionHandler = h;
-	}
-
-	public synchronized void onCompletionResolve(CompletionResolveHandler h) {
-		Assert.isNull("A completionResolveHandler handler is already set, multiple handlers not supported yet", completionResolveHandler);
-		this.completionResolveHandler = h;
-	}
-
-	public synchronized void onDefinition(DefinitionHandler h) {
-		Assert.isNull("A defintion handler is already set, multiple handlers not supported yet", definitionHandler);
-		this.definitionHandler = h;
-	}
-
-	public synchronized void onReferences(ReferencesHandler h) {
-		Assert.isNull("A references handler is already set, multiple handlers not supported yet", referencesHandler);
-		this.referencesHandler = h;
 	}
 
 	/**
 	 * Gets all documents this service is tracking, generally these are the documents that have been opened / changed,
 	 * and not yet closed.
 	 */
-	public synchronized Collection<TextDocument> getAll() {
-		return documents.values().stream()
-				.map((td) -> td.getDocument())
+	public Collection<TextDocument> getAll() {
+		return documentSnapshots.values().stream()
 				.collect(Collectors.toList());
 	}
 
 	@Override
-	public final void didChange(DidChangeTextDocumentParams params) {
-	  async.execute(() -> {
+	public void didOpen(DidOpenTextDocumentParams params) {
+		log.info("change arrived: " + params.getTextDocument().getVersion());
+
+		TextDocumentItem docId = params.getTextDocument();
+
+		String url = docId.getUri();
+		LanguageId languageId = LanguageId.of(docId.getLanguageId());
+		int version = docId.getVersion();
+
+		if (url != null) {
+
+			String text = params.getTextDocument().getText();
+			TrackedDocument td = createDocument(url, languageId, version, text).open();
+			
+			log.debug("Opened " + td.getOpenCount() + " times: " + url);
+			TextDocument doc = td.getDocument();
+			
+			TextDocument snapshot = doc.copy();
+			documentSnapshots.put(url, snapshot);
+
+			documentOpenListeners.fire(snapshot);
+
+			TextDocumentContentChangeEvent change = new TextDocumentContentChangeEvent(text);
+			TextDocumentContentChange evt = new TextDocumentContentChange(snapshot, ImmutableList.of(change));
+
+			documentChangeListeners.fire(evt);
+		}
+	}
+
+	@Override
+	public void didChange(DidChangeTextDocumentParams params) {
+		long start = System.currentTimeMillis();
+
+		log.info("change arrived: " + params.getTextDocument().getVersion());
+
 		try {
 			VersionedTextDocumentIdentifier docId = params.getTextDocument();
 			String url = docId.getUri();
-//			Log.debug("didChange: "+url);
+
 			if (url != null) {
-				TextDocument doc = getDocument(url);
+				TextDocument doc = getInternalDocument(url);
+
 				if (doc != null) {
 					List<TextDocumentContentChangeEvent> changes = params.getContentChanges();
 					doc.apply(params);
-					didChangeContent(doc, changes);
+					
+					TextDocument snapshot = doc.copy();
+					documentSnapshots.put(url, snapshot);
+					documentChangeListeners.fire(new TextDocumentContentChange(snapshot, changes));
 				}
 			}
 		} catch (BadLocationException e) {
 			log.error("", e);
 		}
-	  });
-	}
-
-	@Override
-	public void didOpen(DidOpenTextDocumentParams params) {
-	  async.execute(() -> {
-		TextDocumentItem docId = params.getTextDocument();
-		String url = docId.getUri();
-		//Log.info("didOpen: "+params.getTextDocument().getUri());
-		LanguageId languageId = LanguageId.of(docId.getLanguageId());
-		int version = docId.getVersion();
-		if (url != null) {
-
-			String text = params.getTextDocument().getText();
-			TrackedDocument td = createDocument(url, languageId, version, text).open();
-			log.debug("Opened " + td.getOpenCount() + " times: " + url);
-			TextDocument doc = td.getDocument();
-
-			documentOpenListeners.fire(doc);
-
-			TextDocumentContentChangeEvent change = new TextDocumentContentChangeEvent() {
-				@Override
-				public Range getRange() {
-					return null;
-				}
-
-				@Override
-				public Integer getRangeLength() {
-					return null;
-				}
-
-				@Override
-				public String getText() {
-					return text;
-				}
-			};
-			TextDocumentContentChange evt = new TextDocumentContentChange(doc, ImmutableList.of(change));
-			documentChangeListeners.fire(evt);
-		}
-	  });
+		
+		long end = System.currentTimeMillis();
+		log.info("change message work done in " + (end - start) + "ms");
 	}
 
 	@Override
 	public void didClose(DidCloseTextDocumentParams params) {
-	  async.execute(() -> {
-		//Log.info("didClose: "+params.getTextDocument().getUri());
 		String url = params.getTextDocument().getUri();
-		if (url!=null) {
+
+		if (url != null) {
+
 			TrackedDocument doc = documents.get(url);
 			if (doc != null) {
+
 				if (doc.close()) {
+					documents.remove(url);
+					TextDocument lastSnapshot = documentSnapshots.remove(url);
+
 					log.info("Closed: "+url);
 					//Clear diagnostics when a file is closed. This makes the errors disapear when the language is changed for
 					// a document (this resulst in a dicClose even as being sent to the language server if that changes make the
 					// document go 'out of scope'.
 					publishDiagnostics(params.getTextDocument(), ImmutableList.of());
-					documentCloseListeners.fire(doc.getDocument());
-					documents.remove(url);
+
+					documentCloseListeners.fire(lastSnapshot);
 				} else {
 					log.warn("Close event ignored! Assuming document still open because openCount = "+doc.getOpenCount());
 				}
@@ -250,11 +199,6 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 				log.warn("Document closed, but it didn't exist! Close event ignored");
 			}
 		}
-	  });
-	}
-
-	void didChangeContent(TextDocument doc, List<TextDocumentContentChangeEvent> changes) {
-		documentChangeListeners.fire(new TextDocumentContentChange(doc, changes));
 	}
 
 	public void onDidOpen(Consumer<TextDocument> l) {
@@ -277,24 +221,24 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 		documentSaveListeners = builder.build();
 	}
 
-	public synchronized TextDocument getDocument(String url) {
+	public TextDocument getLatestSnapshot(String url) {
+		return documentSnapshots.get(url);
+	}
+
+	public TextDocument getLatestSnapshot(TextDocumentPositionParams params) {
+		return getLatestSnapshot(params.getTextDocument().getUri());
+	}
+	
+	private TextDocument getInternalDocument(String url) {
 		TrackedDocument doc = documents.get(url);
 		return doc != null ? doc.getDocument() : null;
 	}
-
-	private synchronized TrackedDocument createDocument(String url, LanguageId languageId, int version, String text) {
-		TrackedDocument existingDoc = documents.get(url);
-
-		if (existingDoc != null) {
-			log.warn("Creating document ["+url+"] but it already exists. Reusing existing!");
-			return existingDoc;
-		}
-
-		TrackedDocument doc = new TrackedDocument(new TextDocument(url, languageId, version, text));
-		documents.put(url, doc);
-		return doc;
+	
+	private TrackedDocument createDocument(final String url, final LanguageId languageId, final int version, final String text) {
+		return documents.computeIfAbsent(url, key -> new TrackedDocument(new TextDocument(url, languageId, version, text)));
 	}
 
+
 	public final static CompletionList NO_COMPLETIONS = new CompletionList(false, Collections.emptyList());
 	public final static Hover NO_HOVER = new Hover(ImmutableList.of(), null);
 	public final static List<? extends Location> NO_REFERENCES = ImmutableList.of();
@@ -304,8 +248,10 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 
 	@Override
 	public CompletableFuture<Either<List<CompletionItem>, CompletionList>> completion(CompletionParams position) {
+		log.info("completion request arrived: " + position.getTextDocument().getUri());
+		
 		CompletionHandler h = completionHandler;
-		if (h!=null) {
+		if (h != null) {
 			return completionHandler.handle(position)
 					.map(Either::<List<CompletionItem>, CompletionList>forRight)
 					.toFuture();
@@ -316,13 +262,16 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 	@Override
 	public CompletableFuture<CompletionItem> resolveCompletionItem(CompletionItem unresolved) {
 		log.info("Completion item resolve request received: {}", unresolved.getLabel());
-		return async.invoke(() -> {
+		
+		return CompletableFutures.computeAsync(cancelToken -> {
 			try {
 				CompletionResolveHandler h = completionResolveHandler;
-				if (h!=null) {
+				if (h != null) {
 					log.info("Completion item resolve request starting {}", unresolved.getLabel());
 					return h.handle(unresolved);
 				}
+			} catch (Exception e) {
+				log.warn("exception resolving completion item", e);
 			} finally {
 				log.info("Completion item resolve request terminated.");
 			}
@@ -333,10 +282,18 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 	@Override
 	public CompletableFuture<Hover> hover(HoverParams hoverParams) {
 		log.debug("hover requested for {}", hoverParams.getPosition());
-		long timeout = props.getHoverTimeout();
-		return timeout <= 0 ? async.invoke(() -> computeHover(hoverParams)) : async.invoke(Duration.ofMillis(timeout), () -> computeHover(hoverParams), Mono.fromRunnable(() -> {
-			log.error("Hover Request handler timed out after {} ms.", timeout);
-		}));
+		
+		return CompletableFutures.computeAsync(cancelToken -> {
+			return computeHover(hoverParams);
+		});
+		
+		
+		// TODO: timeout still necessary ?????
+		
+//		long timeout = props.getHoverTimeout();
+//		return timeout <= 0 ? async.invoke(() -> computeHover(hoverParams)) : async.invoke(Duration.ofMillis(timeout), () -> computeHover(hoverParams), Mono.fromRunnable(() -> {
+//			log.error("Hover Request handler timed out after {} ms.", timeout);
+//		}));
 	}
 	
 	private Hover computeHover(HoverParams hoverParams) {
@@ -353,20 +310,15 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 		}
 	}
 
-	@Override
-	public CompletableFuture<SignatureHelp> signatureHelp(SignatureHelpParams signatureHelpParams) {
-		return CompletableFuture.completedFuture(null);
-	}
-
 	@Override
 	public CompletableFuture<Either<List<? extends Location>, List<? extends LocationLink>>> definition(
 			DefinitionParams definitionParams) {
 
 		DefinitionHandler h = this.definitionHandler;
 		if (h != null) {
-			return async.invoke(() -> {
+			return CompletableFutures.computeAsync(cancelToken -> {
 				List<LocationLink> locations = h.handle(definitionParams);
-				if (locations==null) {
+				if (locations == null) {
 					// vscode client does not like to receive null result. See: https://github.com/spring-projects/sts4/issues/309
 					locations = ImmutableList.of();
 				}
@@ -382,27 +334,42 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 				}
 			});
 		}
-		return CompletableFuture.completedFuture(Either.forLeft(ImmutableList.of()));
+		else {
+			return CompletableFuture.completedFuture(Either.forLeft(ImmutableList.of()));
+		}
 	}
 
 	@Override
 	public CompletableFuture<List<? extends Location>> references(ReferenceParams params) {
-	  return async.invoke(() -> {
 		ReferencesHandler h = this.referencesHandler;
 		if (h != null) {
-			List<? extends Location> list = h.handle(params);
-			return list != null && list.isEmpty() ? null : list;
+
+			return CompletableFutures.computeAsync(cancelToken -> {
+				List<? extends Location> list = h.handle(params);
+				return list != null && list.isEmpty() ? null : list;
+			});
+		}
+		else {
+			return CompletableFuture.completedFuture(ImmutableList.of());
 		}
-		return null;
-	  });
 	}
 
 	@Override
 	public CompletableFuture<List<Either<SymbolInformation, DocumentSymbol>>> documentSymbol(DocumentSymbolParams params) {
-		return async.invoke(() -> {
-			DocumentSymbolHandler h = this.documentSymbolHandler;
-			if (h!=null) {
-				server.waitForReconcile();
+		DocumentSymbolHandler h = this.documentSymbolHandler;
+		if (h != null) {
+			
+			return CompletableFutures.computeAsync(cancelToken -> {
+				cancelToken.checkCanceled();
+
+				try {
+					server.waitForReconcile();
+				} catch (Exception e) {
+					log.warn("error while waiting for reconcile", e);
+				}
+
+				cancelToken.checkCanceled();
+
 				if (server.hasHierarchicalDocumentSymbolSupport() && h instanceof HierarchicalDocumentSymbolHandler) {
 					List<? extends DocumentSymbol> r = ((HierarchicalDocumentSymbolHandler)h).handleHierarchic(params);
 					//handle it when symbolHandler is sloppy and returns null instead of empty list.
@@ -418,33 +385,40 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 							: r.stream().map(symbolInfo -> Either.<SymbolInformation, DocumentSymbol>forLeft(symbolInfo))
 										.collect(Collectors.toList());
 				}
-			}
-			return ImmutableList.of();
-		});
+			});
+		}
+		else {
+			return CompletableFuture.completedFuture(ImmutableList.of());
+		}
 	}
 
 	@Override
 	public CompletableFuture<List<Either<Command, CodeAction>>> codeAction(CodeActionParams params) {
-	  return async.invoke(() -> {
+		// this doesn't happen async, because it accesses the internal documents structure
+		// and therefore needs to be executed as part of the main LSP message queue
+
 		TrackedDocument doc = documents.get(params.getTextDocument().getUri());
-		if (doc!=null) {
+
+		if (doc != null) {
 			ImmutableList<Either<Command,CodeAction>> list = doc.getQuickfixes().stream()
-				.filter((fix) -> fix.appliesTo(params.getRange(), params.getContext()))
-				.map(Quickfix::getCodeAction)
-				.map(command -> Either.<Command, CodeAction>forLeft(command))
-				.collect(CollectorUtil.toImmutableList());
-			return list;
+					.filter((fix) -> fix.appliesTo(params.getRange(), params.getContext()))
+					.map(Quickfix::getCodeAction)
+					.map(command -> Either.<Command, CodeAction>forLeft(command))
+					.collect(CollectorUtil.toImmutableList());
+			return CompletableFuture.completedFuture(list);
 		} else {
-			return ImmutableList.of();
+			return CompletableFuture.completedFuture(ImmutableList.of());
 		}
-	  });
 	}
 
 	@Override
 	public CompletableFuture<List<? extends CodeLens>> codeLens(CodeLensParams params) {
 		CodeLensHandler handler = this.codeLensHandler;
+
 		if (handler != null) {
-			return async.invoke(() -> handler.handle(params));
+			return CompletableFutures.computeAsync(cancelToken -> {
+				return handler.handle(params);
+			});
 		}
 		return CompletableFuture.completedFuture(Collections.emptyList());
 	}
@@ -453,8 +427,58 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 	public CompletableFuture<CodeLens> resolveCodeLens(CodeLens unresolved) {
 		CodeLensResolveHandler handler = this.codeLensResolveHandler;
 		if (handler != null) {
-			return async.invoke(() -> handler.handle(unresolved));
+			
+			return CompletableFutures.computeAsync(cancelToken -> {
+				return handler.handle(unresolved);
+			});
+
 		}
+		else {
+			return CompletableFuture.completedFuture(null);
+		}
+	}
+
+	@Override
+	public void didSave(DidSaveTextDocumentParams params) {
+		// Workaround for PT 147263283, where error markers in STS are lost on document save.
+		// STS 3.9.0 does not use the LSP4E editor for edit manifest.yml, which correctly retains error markers after save.
+		// Instead, because the LSP4E editor is missing support for hovers and completions, STS 3.9.0 uses its own manifest editor
+		// which extends the YEdit editor. This YEdit editor has a problem, where on save, all error markers are deleted.
+		// When STS uses the LSP4E editor and no longer needs its own YEdit-based editor, the issue with error markers disappearing
+		// on save should not be a problem anymore, and the workaround below will no longer be needed.
+		if (documentSaveListeners != null) {
+			CompletableFuture.runAsync(() -> {
+				TextDocumentIdentifier docId = params.getTextDocument();
+				String url = docId.getUri();
+				log.debug("didSave: "+url);
+				if (url != null) {
+					TextDocument doc = getLatestSnapshot(url);
+					if (doc != null) {
+						for (Consumer<TextDocumentSaveChange> l : documentSaveListeners) {
+							l.accept(new TextDocumentSaveChange(doc));
+						}
+					}
+				}
+			});
+		}
+	}
+
+	@Override
+	public CompletableFuture<List<? extends DocumentHighlight>> documentHighlight(DocumentHighlightParams highlightParams) {
+		DocumentHighlightHandler handler = this.documentHighlightHandler;
+		if (handler != null) {
+			return CompletableFutures.computeAsync(cancelToken -> {
+				return handler.handle(highlightParams);
+
+			});
+		}
+		else {
+			return CompletableFuture.completedFuture(Collections.emptyList());
+		}
+	}
+
+	@Override
+	public CompletableFuture<SignatureHelp> signatureHelp(SignatureHelpParams signatureHelpParams) {
 		return CompletableFuture.completedFuture(null);
 	}
 
@@ -477,35 +501,14 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 	public CompletableFuture<WorkspaceEdit> rename(RenameParams params) {
 		return CompletableFuture.completedFuture(null);
 	}
-
-	@Override
-	public void didSave(DidSaveTextDocumentParams params) {
-		// Workaround for PT 147263283, where error markers in STS are lost on document save.
-		// STS 3.9.0 does not use the LSP4E editor for edit manifest.yml, which correctly retains error markers after save.
-		// Instead, because the LSP4E editor is missing support for hovers and completions, STS 3.9.0 uses its own manifest editor
-		// which extends the YEdit editor. This YEdit editor has a problem, where on save, all error markers are deleted.
-		// When STS uses the LSP4E editor and no longer needs its own YEdit-based editor, the issue with error markers disappearing
-		// on save should not be a problem anymore, and the workaround below will no longer be needed.
-	  async.execute(() -> {
-		if (documentSaveListeners != null) {
-			TextDocumentIdentifier docId = params.getTextDocument();
-			String url = docId.getUri();
-			log.debug("didSave: "+url);
-			if (url != null) {
-				TextDocument doc = getDocument(url);
-				if (doc != null) {
-					for (Consumer<TextDocumentSaveChange> l : documentSaveListeners) {
-						l.accept(new TextDocumentSaveChange(doc));
-					}
-				}
-			}
-		}
-	  });
-	}
+	
+	//
+	//
+	//
 
 	public void publishDiagnostics(TextDocumentIdentifier docId, Collection<Diagnostic> diagnostics) {
 		LanguageClient client = server.getClient();
-		if (client!=null && diagnostics!=null) {
+		if (client != null && diagnostics != null) {
 			PublishDiagnosticsParams params = new PublishDiagnosticsParams();
 			params.setUri(docId.getUri());
 			params.setDiagnostics(ImmutableList.copyOf(diagnostics));
@@ -515,67 +518,82 @@ public class SimpleTextDocumentService implements TextDocumentService, DocumentE
 
 	public void setQuickfixes(TextDocumentIdentifier docId, List<Quickfix<?>> quickfixes) {
 		TrackedDocument td = documents.get(docId.getUri());
-		if (td!=null) {
+		if (td != null) {
 			td.setQuickfixes(quickfixes);
 		}
 	}
 
-	public synchronized TextDocument get(TextDocumentPositionParams params) {
-		return get(params.getTextDocument().getUri());
+	//
+	//
+	//
+	
+	public synchronized void onHover(HoverHandler h) {
+		Assert.isNull("A hover handler is already set, multiple handlers not supported yet", hoverHandler);
+		this.hoverHandler = h;
 	}
 
-	public synchronized TextDocument get(String uri) {
-		TrackedDocument td = documents.get(uri);
-		return td == null ? null : td.getDocument();
-	}
-
-	@Override
-	public CompletableFuture<List<? extends DocumentHighlight>> documentHighlight(DocumentHighlightParams highlightParams) {
-	  return async.invoke(() -> {
-		DocumentHighlightHandler handler = this.documentHighlightHandler;
-		if (handler != null) {
-			return handler.handle(highlightParams);
-		}
-		return NO_HIGHLIGHTS;
-	  });
-	}
-
-	public boolean hasDefinitionHandler() {
-		return definitionHandler!=null;
-	}
-
-	public boolean hasReferencesHandler() {
-		return this.referencesHandler!=null;
-	}
-
-	public boolean hasDocumentSymbolHandler() {
-		return this.documentSymbolHandler!=null;
-	}
-
-	public boolean hasDocumentHighlightHandler() {
-		return this.documentHighlightHandler!=null;
+	public synchronized void onCodeLens(CodeLensHandler h) {
+		Assert.isNull("A code lens handler is already set, multiple handlers not supported yet", codeLensHandler);
+		this.codeLensHandler = h;
 	}
 
 	public boolean hasCodeLensHandler() {
 		return this.codeLensHandler != null;
 	}
 
+	public synchronized void onCodeLensResolve(CodeLensResolveHandler h) {
+		Assert.isNull("A code lens resolve handler is already set, multiple handlers not supported yet", codeLensResolveHandler);
+		this.codeLensResolveHandler = h;
+	}
+
 	public boolean hasCodeLensResolveProvider() {
 		return this.codeLensResolveHandler != null;
 	}
 
-	public TextDocument getDocumentSnapshot(TextDocumentIdentifier textDocumentIdentifier) {
-		try {
-			return async.invoke(() -> {
-				TextDocument doc = get(textDocumentIdentifier.getUri());
-				if (doc!=null) {
-					return doc.copy();
-				}
-				return null;
-			}).get();
-		} catch (Exception e) {
-			throw ExceptionUtil.unchecked(e);
-		}
+	public synchronized void onDocumentSymbol(DocumentSymbolHandler h) {
+		Assert.isNull("A DocumentSymbolHandler is already set, multiple handlers not supported yet", documentSymbolHandler);
+		this.documentSymbolHandler = h;
+	}
+
+	public boolean hasDocumentSymbolHandler() {
+		return this.documentSymbolHandler != null;
+	}
+
+	public synchronized void onDocumentHighlight(DocumentHighlightHandler h) {
+		Assert.isNull("A DocumentHighlightHandler is already set, multiple handlers not supported yet", documentHighlightHandler);
+		this.documentHighlightHandler = h;
+	}
+
+	public boolean hasDocumentHighlightHandler() {
+		return this.documentHighlightHandler != null;
+	}
+
+	 public synchronized void onCompletion(CompletionHandler h) {
+		Assert.isNull("A completion handler is already set, multiple handlers not supported yet", completionHandler);
+		this.completionHandler = h;
+	}
+
+	public synchronized void onCompletionResolve(CompletionResolveHandler h) {
+		Assert.isNull("A completionResolveHandler handler is already set, multiple handlers not supported yet", completionResolveHandler);
+		this.completionResolveHandler = h;
+	}
+
+	public synchronized void onDefinition(DefinitionHandler h) {
+		Assert.isNull("A defintion handler is already set, multiple handlers not supported yet", definitionHandler);
+		this.definitionHandler = h;
+	}
+
+	public boolean hasDefinitionHandler() {
+		return definitionHandler != null;
+	}
+
+	public synchronized void onReferences(ReferencesHandler h) {
+		Assert.isNull("A references handler is already set, multiple handlers not supported yet", referencesHandler);
+		this.referencesHandler = h;
+	}
+
+	public boolean hasReferencesHandler() {
+		return this.referencesHandler != null;
 	}
 
 }

headless-services/commons/commons-util/src/main/java/org/springframework/ide/vscode/commons/util/text/TextDocument.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016, 2017 Pivotal, Inc.
+ * Copyright (c) 2016, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -87,7 +87,7 @@ public class TextDocument implements IDocument {
 
 	public synchronized void apply(DidChangeTextDocumentParams params) throws BadLocationException {
 		int newVersion = params.getTextDocument().getVersion();
-		if (version<newVersion) {
+		if (version < newVersion) {
 			for (TextDocumentContentChangeEvent change : params.getContentChanges()) {
 				apply(change);
 			}
@@ -290,7 +290,7 @@ public class TextDocument implements IDocument {
 	}
 
 	public TextDocumentIdentifier getId() {
-		if (uri!=null) {
+		if (uri != null) {
 			return new TextDocumentIdentifier(uri);
 		}
 		return null;

headless-services/commons/commons-yaml/src/main/java/org/springframework/ide/vscode/commons/yaml/quickfix/YamlQuickfixes.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -56,7 +56,8 @@ public class YamlQuickfixes {
 		MISSING_PROP_FIX = r.register("MISSING_PROP_FIX", (Object _params) -> {
 			MissingPropertiesData params = gson.fromJson((JsonElement)_params, MissingPropertiesData.class);
 			try {
-				TextDocument _doc = textDocumentService.getDocument(params.getUri());
+				TextDocument _doc = textDocumentService.getLatestSnapshot(params.getUri());
+
 				if (_doc != null) {
 					YamlDocument doc = new YamlDocument(_doc, structureProvider);
 					SNode root = doc.getStructure();
@@ -95,7 +96,8 @@ public class YamlQuickfixes {
 		SIMPLE_TEXT_EDIT = r.register("SIMPLE_TEXT_EDIT", (_params) -> {
 			try {
 				ReplaceStringData params = gson.fromJson((JsonElement)_params, ReplaceStringData.class);
-				TextDocument _doc = textDocumentService.getDocument(params.getUri());
+				TextDocument _doc = textDocumentService.getLatestSnapshot(params.getUri());
+
 				if (_doc != null) {
 					return new QuickfixEdit(
 						new WorkspaceEdit(

headless-services/commons/commons-yaml/src/main/java/org/springframework/ide/vscode/commons/yaml/reconcile/TypeBasedYamlSymbolHandler.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -64,7 +64,8 @@ public class TypeBasedYamlSymbolHandler implements DocumentSymbolHandler {
 	@Override
 	public List<? extends SymbolInformation> handle(DocumentSymbolParams params) {
 		Builder<SymbolInformation> builder = ImmutableList.builder();
-		TextDocument doc = documents.getDocument(params.getTextDocument().getUri());
+
+		TextDocument doc = documents.getLatestSnapshot(params.getTextDocument().getUri());
 		if (doc != null) {
 			for (Entry<Node, YType> entry : astTypeCache.getNodeTypes(params.getTextDocument().getUri()).getTypes().entrySet()) {
 				if (definitionTypes.contains(entry.getValue())) {

headless-services/commons/language-server-starter/src/main/java/org/springframework/ide/vscode/languageserver/starter/LanguageServerAutoConf.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2018, 2019 Pivotal, Inc.
+ * Copyright (c) 2018, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -86,9 +86,11 @@ public class LanguageServerAutoConf {
 					handlers.put(l, h);
 				}
 			}
+
 			ImmutableMap<LanguageId, DefinitionHandler> immutableMap = ImmutableMap.copyOf(handlers);
 			return () -> documents.onDefinition((position) -> {
-				TextDocument doc = documents.get(position.getTextDocument().getUri());
+				TextDocument doc = documents.getLatestSnapshot(position);
+
 				if (doc != null) {
 					LanguageId language = doc.getLanguageId();
 					DefinitionHandler handler = immutableMap.get(language);

headless-services/concourse-language-server/src/main/java/org/springframework/ide/vscode/concourse/ConcourseDefinitionFinder.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -92,7 +92,7 @@ public class ConcourseDefinitionFinder extends SimpleDefinitionFinder {
 	@Override
 	public List<LocationLink> handle(DefinitionParams params) {
 		try {
-			TextDocument doc = server.getTextDocumentService().get(params);
+			TextDocument doc = server.getTextDocumentService().getLatestSnapshot(params);
 			if (doc!=null) {
 				YamlFileAST ast = asts.getSafeAst(doc, false);
 				if (ast!=null) {

headless-services/concourse-language-server/src/main/java/org/springframework/ide/vscode/concourse/ConcourseLanguageServerInitializer.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2016 Pivotal, Inc.
+ * Copyright (c) 2016, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -142,8 +142,8 @@ public class ConcourseLanguageServerInitializer {
 //		});
 
 		documents.onCompletion(params -> {
-			TextDocument doc = documents.get(params);
-			if (doc!=null) {
+			TextDocument doc = documents.getLatestSnapshot(params);
+			if (doc != null) {
 				if (LanguageId.CONCOURSE_PIPELINE.equals(doc.getLanguageId())) {
 					return forPipelines.completionEngine.getCompletions(params);
 				} else if (LanguageId.CONCOURSE_TASK.equals(doc.getLanguageId())) {
@@ -159,8 +159,8 @@ public class ConcourseLanguageServerInitializer {
 		documents.onHover(params -> {
 			log.debug("Concourse hover handler starting");
 			try {
-				TextDocument doc = documents.get(params);
-				if (doc!=null) {
+				TextDocument doc = documents.getLatestSnapshot(params);
+				if (doc != null) {
 					LanguageId languageId = doc.getLanguageId();
 					if (LanguageId.CONCOURSE_PIPELINE.equals(doc.getLanguageId())) {
 						return forPipelines.hoverEngine.handle(params);

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/app/PropertiesJavaDefinitionHandler.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2018, 2020 Pivotal, Inc.
+ * Copyright (c) 2018, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -63,7 +63,7 @@ public class PropertiesJavaDefinitionHandler implements DefinitionHandler, Langu
 	@Override
 	public List<LocationLink> handle(DefinitionParams definitionParams) {
 		try {
-			TextDocument doc = documents.get(definitionParams);
+			TextDocument doc = documents.getLatestSnapshot(definitionParams);
 			TypeUtil typeUtil = params.typeUtilProvider.getTypeUtil(sourceLinks, doc);
 			FuzzyMap<PropertyInfo> index = params.indexProvider.getIndex(doc).getProperties();
 			int offset;

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/app/XmlBeansConfigDefinitionHandler.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019, 2020 Pivotal, Inc.
+ * Copyright (c) 2019, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -99,7 +99,7 @@ public class XmlBeansConfigDefinitionHandler implements DefinitionHandler, Langu
 		
 		JavaTypeHyperlinkProvider javaTypeHyperlinkProvider = new JavaTypeHyperlinkProvider(projectFinder, locationProvider);
 		PropertyNameHyperlinkProvider propertyNameHyperlinkProvider = new PropertyNameHyperlinkProvider(projectFinder, locationProvider);
-		BeanRefHyperlinkProvider beanRefHyperlinkProvider = new BeanRefHyperlinkProvider(projectFinder, symbolIndex, documents);
+		BeanRefHyperlinkProvider beanRefHyperlinkProvider = new BeanRefHyperlinkProvider(projectFinder, symbolIndex);
 		
 		List<JavaTypeHyperlinkProvider> typeHandlersOnly = Arrays.asList(javaTypeHyperlinkProvider);
 		List<PropertyNameHyperlinkProvider> propertyNameHandlers = Arrays.asList(propertyNameHyperlinkProvider);
@@ -143,7 +143,7 @@ public class XmlBeansConfigDefinitionHandler implements DefinitionHandler, Langu
 	public List<LocationLink> handle(DefinitionParams params) {
 		try {
 			if (config.isSpringXMLSupportEnabled() && config.areXmlHyperlinksEnabled()) {
-				TextDocument doc = documents.get(params);
+				TextDocument doc = documents.getLatestSnapshot(params);
 				if (doc != null) {
 					String content = doc.get();
 	

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/app/YamlPropertiesJavaDefinitionHandler.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2018, 2020 Pivotal, Inc.
+ * Copyright (c) 2018, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -70,7 +70,7 @@ public class YamlPropertiesJavaDefinitionHandler implements DefinitionHandler, L
 	@Override
 	public List<LocationLink> handle(DefinitionParams definitionParams) {
 		try {
-			TextDocument doc = documents.get(definitionParams);
+			TextDocument doc = documents.getLatestSnapshot(definitionParams);
 			int offset = doc.toOffset(definitionParams.getPosition());
 			YamlFileAST ast = getAst(doc);
 			if (ast != null) {

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/handlers/BootJavaCodeLensEngine.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2018 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -40,8 +40,8 @@ public class BootJavaCodeLensEngine implements CodeLensHandler {
 		SimpleTextDocumentService documents = server.getTextDocumentService();
 		String docURI = params.getTextDocument().getUri();
 
-		if (documents.get(docURI) != null) {
-			TextDocument doc = documents.get(docURI).copy();
+		TextDocument doc = documents.getLatestSnapshot(docURI);
+		if (doc != null) {
 			// Spring Boot LS get events from boot properties files as well, so filter them out
 			if (server.getInterestingLanguages().contains(doc.getLanguageId())) {
 				try {

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/handlers/BootJavaDocumentHighlightEngine.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2018, 2020 Pivotal, Inc.
+ * Copyright (c) 2018, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -42,10 +42,9 @@ public class BootJavaDocumentHighlightEngine implements DocumentHighlightHandler
 	@Override
 	public List<DocumentHighlight> handle(DocumentHighlightParams params) {
 		SimpleTextDocumentService documents = server.getTextDocumentService();
-		String docURI = params.getTextDocument().getUri();
-
-		if (documents.get(docURI) != null) {
-			TextDocument doc = documents.get(docURI).copy();
+		TextDocument doc = documents.getLatestSnapshot(params);
+		
+		if (doc != null) {
 			// Spring Boot LS get events from boot properties files as well, so filter them out
 			if (doc != null && server.getInterestingLanguages().contains(doc.getLanguageId())) {
 				try {

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/handlers/BootJavaHoverProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -73,8 +73,9 @@ public class BootJavaHoverProvider implements HoverHandler {
 	@Override
 	public Hover handle(HoverParams params) {
 		SimpleTextDocumentService documents = server.getTextDocumentService();
-		if (documents.get(params) != null) {
-			TextDocument doc = documents.get(params).copy();
+		TextDocument doc = documents.getLatestSnapshot(params);
+		
+		if (doc != null) {
 			// Spring Boot LS get events from boot properties files as well, so filter them out
 			if (server.getInterestingLanguages().contains(doc.getLanguageId())) {
 				try {

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/handlers/BootJavaReferencesHandler.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -53,8 +53,9 @@ public class BootJavaReferencesHandler implements ReferencesHandler {
 
 	@Override
 	public List<? extends Location> handle(ReferenceParams params) {
-		SimpleTextDocumentService documents = server.getTextDocumentService();
-		TextDocument doc = documents.get(params).copy();
+		SimpleTextDocumentService documents = server.getTextDocumentService();		
+		TextDocument doc = documents.getLatestSnapshot(params);
+
 		if (doc != null) {
 			// Spring Boot LS get events from boot properties files as well, so filter them out
 			if (server.getInterestingLanguages().contains(doc.getLanguageId())) {

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/livehover/v2/SpringProcessLiveHoverUpdater.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2019 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -37,10 +37,10 @@ public class SpringProcessLiveHoverUpdater {
 
 	private final SimpleLanguageServer server;
 	private final BootJavaHoverProvider hoverProvider;
+	private final JavaProjectFinder projectFinder;
 
-	private boolean highlightsEnabled = true;
-	private JavaProjectFinder projectFinder;
 	private final Map<String, AtomicReference<IJavaProject>> watchedDocs;
+	private boolean highlightsEnabled = true;
 
 	public SpringProcessLiveHoverUpdater(
 			SimpleLanguageServer server,
@@ -56,11 +56,7 @@ public class SpringProcessLiveHoverUpdater {
 		server.getTextDocumentService().onDidChangeContent(params -> {
 			TextDocument doc = params.getDocument();
 			if (BootJavaLanguageServerComponents.LANGUAGES.contains(doc.getLanguageId())) {
-				try {
-					watchDocument(doc.getUri());
-				} catch (Throwable t) {
-					log.error("", t);
-				}
+				watchDocument(doc.getUri());
 			}
 		});
 		
@@ -81,7 +77,14 @@ public class SpringProcessLiveHoverUpdater {
 
 	public void watchDocument(String docURI) {
 		this.watchedDocs.putIfAbsent(docURI, new AtomicReference<IJavaProject>());
-		updateDoc(docURI);
+		
+		CompletableFuture.runAsync(() -> {
+			try {
+				updateDoc(docURI);
+			} catch (Throwable t) {
+				log.error("", t);
+			}
+		});
 	}
 
 	public void unwatchDocument(String docURI) {
@@ -89,6 +92,7 @@ public class SpringProcessLiveHoverUpdater {
 		cleanupLiveHints(docURI);
 	}
 
+	// runs async
 	private void updateDoc(String docURI) {
 		try {
 			IJavaProject project = getCachedProject(docURI);
@@ -99,6 +103,7 @@ public class SpringProcessLiveHoverUpdater {
 		}
 	}
 
+	// runs async
 	private void update() {
 		if (this.watchedDocs.size() > 0) {
 			try {
@@ -112,10 +117,11 @@ public class SpringProcessLiveHoverUpdater {
 		}
 	}
 
+	// runs async
 	private void update(String docURI, IJavaProject project) {
 		if (highlightsEnabled) {
 			try {
-				TextDocument doc = this.server.getTextDocumentService().get(docURI);
+				TextDocument doc = this.server.getTextDocumentService().getLatestSnapshot(docURI);
 				if (doc != null) {
 					CodeLens[] infos = this.hoverProvider.getLiveHoverHints(doc, project);
 					publishLiveHints(docURI, infos);
@@ -126,6 +132,7 @@ public class SpringProcessLiveHoverUpdater {
 		}
 	}
 
+	// runs async
 	private IJavaProject getCachedProject(String docURI) {
 		AtomicReference<IJavaProject> reference = this.watchedDocs.get(docURI);
 		if (reference != null) {
@@ -141,8 +148,9 @@ public class SpringProcessLiveHoverUpdater {
 		return null;
 	}
 
+	// runs async
 	private IJavaProject identifyProject(String docURI) {
-		TextDocument doc = this.server.getTextDocumentService().get(docURI);
+		TextDocument doc = this.server.getTextDocumentService().getLatestSnapshot(docURI);
 		if (doc != null) {
 			return projectFinder.find(doc.getId()).orElse(null);
 		}
@@ -151,8 +159,9 @@ public class SpringProcessLiveHoverUpdater {
 		}
 	}
 
+	// runs sync or async
 	private void publishLiveHints(String docURI, CodeLens[] codeLenses) {
-		TextDocument doc = server.getTextDocumentService().get(docURI);
+		TextDocument doc = server.getTextDocumentService().getLatestSnapshot(docURI);
 		if (doc != null) {
 			int version = doc.getVersion();
 			VersionedTextDocumentIdentifier id = new VersionedTextDocumentIdentifier(docURI, version);
@@ -160,8 +169,9 @@ public class SpringProcessLiveHoverUpdater {
 		}
 	}
 
+	// runs sync or async
 	private void cleanupLiveHints(String docURI) {
 		publishLiveHints(docURI, new CodeLens[0]);
 	}
-
+	
 }

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/java/utils/CompilationUnitCache.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017, 2020 Pivotal, Inc.
+ * Copyright (c) 2017, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -18,9 +18,6 @@ import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.locks.ReentrantReadWriteLock;
-import java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock;
-import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
 import java.util.function.Function;
 import java.util.stream.Stream;
 
@@ -45,13 +42,11 @@ import org.springframework.ide.vscode.commons.languageserver.java.JavaProjectFin
 import org.springframework.ide.vscode.commons.languageserver.java.ProjectObserver;
 import org.springframework.ide.vscode.commons.languageserver.util.SimpleLanguageServer;
 import org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService;
-import org.springframework.ide.vscode.commons.util.AsyncRunner;
 import org.springframework.ide.vscode.commons.util.text.TextDocument;
 
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 
-import reactor.core.scheduler.Schedulers;
 import reactor.util.function.Tuple2;
 import reactor.util.function.Tuples;
 
@@ -62,95 +57,94 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 	private static final long CU_ACCESS_EXPIRATION = 1;
 	private JavaProjectFinder projectFinder;
 	private ProjectObserver projectObserver;
-	private Cache<URI, CompilationUnit> uriToCu;
-	private Cache<IJavaProject, Set<URI>> projectToDocs;
-	private Cache<IJavaProject, Tuple2<List<Classpath>, INameEnvironmentWithProgress>> lookupEnvCache;
-	private ProjectObserver.Listener projectListener;
-	private SimpleTextDocumentService documents;
-	private AsyncRunner async;
+	
+	private final ProjectObserver.Listener projectListener;
+	private final SimpleTextDocumentService documentService;
+//	private AsyncRunner async;
 
-	private ReadLock readLock;
-	private WriteLock writeLock;
+	private final Cache<URI, CompilationUnit> uriToCu;
+	private final Cache<IJavaProject, Set<URI>> projectToDocs;
+	private final Cache<IJavaProject, Tuple2<List<Classpath>, INameEnvironmentWithProgress>> lookupEnvCache;
+
+//	private ReadLock readLock;
+//	private WriteLock writeLock;
 
 	public CompilationUnitCache(JavaProjectFinder projectFinder, SimpleLanguageServer server, ProjectObserver projectObserver) {
 		this.projectFinder = projectFinder;
 		this.projectObserver = projectObserver;
-		this.lookupEnvCache = CacheBuilder.newBuilder().build();
 		
 		// PT 154618835 - Avoid retaining the CU in the cache as it consumes memory if it hasn't been
 		// accessed after some time
-		uriToCu = CacheBuilder.newBuilder()
+		this.uriToCu = CacheBuilder.newBuilder()
 				.expireAfterWrite(CU_ACCESS_EXPIRATION, TimeUnit.MINUTES)
 				.build();
-		projectToDocs = CacheBuilder.newBuilder().build();
+		this.projectToDocs = CacheBuilder.newBuilder().build();
+		this.lookupEnvCache = CacheBuilder.newBuilder().build();
 
-		ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-		readLock = lock.readLock();
-		writeLock = lock.writeLock();
+//		ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+//		this.readLock = lock.readLock();
+//		this.writeLock = lock.writeLock();
 
-		this.documents = server == null ? null : server.getTextDocumentService();
-		this.async = server == null ? new AsyncRunner(Schedulers.single()) : server.getAsync();
+		this.documentService = server == null ? null : server.getTextDocumentService();
+//		this.async = server == null ? new AsyncRunner(Schedulers.single()) : server.getAsync();
 		
 
-		if (documents != null) {
-			documents.onDidChangeContent(doc -> invalidateCuForJavaFile(doc.getDocument().getId().getUri()));
-			documents.onDidClose(doc -> invalidateCuForJavaFile(doc.getId().getUri()));
+		// IMPORTANT ===> these notifications arrive within the lsp message loop, so reactions to them have to be fast
+		// and not be blocked by waiting for anything
+		if (documentService != null) {
+			documentService.onDidChangeContent(doc -> invalidateCuForJavaFile(doc.getDocument().getId().getUri()));
+			documentService.onDidClose(doc -> invalidateCuForJavaFile(doc.getId().getUri()));
+		}
+
+		for (IJavaProject project : projectFinder.all()) {
+			logger.info("CU Cache: initial lookup env creation for project <{}>", project.getElementName());
+			loadLookupEnvTuple(project);
 		}
 
-		async.execute(() -> {
-			writeLock.lock();
-			try {
-				for (IJavaProject project : projectFinder.all()) {
-					loadLookupEnvTuple(project);
-				}
-			} finally {
-				writeLock.unlock();
-			}
-		});
 
 		projectListener = new ProjectObserver.Listener() {
 			
 			@Override
 			public void deleted(IJavaProject project) {
 				logger.info("CU Cache: deleted project {}", project.getElementName());
-				async.execute(() -> {
-					writeLock.lock();
-					try {
+//				async.execute(() -> {
+//					writeLock.lock();
+//					try {
 						invalidateProject(project);
-					} finally {
-						writeLock.unlock();
-					}
-				});
+//					} finally {
+//						writeLock.unlock();
+//					}
+//				});
 			}
 			
 			@Override
 			public void created(IJavaProject project) {
 				logger.info("CU Cache: created project {}", project.getElementName());
-				async.execute(() -> {
-					writeLock.lock();
-					try {
+//				async.execute(() -> {
+//					writeLock.lock();
+//					try {
 						invalidateProject(project);
 						// Load the new cache the value right away
 						loadLookupEnvTuple(project);
-					} finally {
-						writeLock.unlock();
-					}
-				});
+//					} finally {
+//						writeLock.unlock();
+//					}
+//				});
 			}
 			
 			@Override
 			public void changed(IJavaProject project) {
 				logger.info("CU Cache: changed project {}", project.getElementName());
-				async.execute(() -> {
-					writeLock.lock();
-					try {
+//				async.execute(() -> {
+//					writeLock.lock();
+//					try {
 						invalidateProject(project);
 						// Load the new cache the value right away
 						loadLookupEnvTuple(project);
-					} finally {
-						writeLock.unlock();
-					}
-				});
+//					} finally {
+//						writeLock.unlock();
+//					}
+//				});
 			}
 		};
 
@@ -182,9 +176,10 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 	}
 
 	public <T> T withCompilationUnit(IJavaProject project, URI uri, Function<CompilationUnit, T> requestor) {
+		logger.info("CU Cache: work item for doc {}", uri.toString());
+
 		if (project != null) {
 
-			readLock.lock();
 			CompilationUnit cu = null;
 
 			try {
@@ -193,20 +188,23 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 					String utiStr = uri.toString();
 					String unitName = utiStr.substring(utiStr.lastIndexOf("/"));
 					CompilationUnit cUnit = parse2(fetchContent(uri).toCharArray(), utiStr, unitName, lookupEnvTuple.getT1(), lookupEnvTuple.getT2());
-					projectToDocs.get(project, () -> new HashSet<>()).add(uri);
+					
+					logger.info("CU Cache: created new AST for {}", uri.toString());
+
 					return cUnit;
 				});
+
 				if (cu != null) {
 					projectToDocs.get(project, () -> new HashSet<>()).add(uri);
 				}
+
 			} catch (Exception e) {
 				logger.error("", e);
-			} finally {
-				readLock.unlock();
 			}
 
 			if (cu != null) {
 				try {
+					logger.info("CU Cache: sync start on AST for {}", uri.toString());
 					synchronized (cu.getAST()) {
 						return requestor.apply(cu);
 					}
@@ -214,6 +212,9 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 				catch (Exception e) {
 					logger.error("", e);
 				}
+				finally {
+					logger.info("CU Cache: sync end on AST for {}", uri.toString());
+				}
 			}
 		}
 
@@ -221,51 +222,6 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 	}
 
 
-	private void invalidateCuForJavaFile(String uriStr) {
-		URI uri = URI.create(uriStr);
-		writeLock.lock();
-		try {
-			uriToCu.invalidate(uri);
-		} finally {
-			writeLock.unlock();
-		}
-	}
-
-//	public static CompilationUnit parse(TextDocument document, IJavaProject project) throws Exception {
-//		String[] classpathEntries = getClasspathEntries(project);
-//		String docURI = document.getUri();
-//		String unitName = docURI.substring(docURI.lastIndexOf("/"));
-//		char[] source = document.get(0, document.getLength()).toCharArray();
-//		return parse(source, docURI, unitName, classpathEntries);
-//	}
-//
-//	public CompilationUnit parse(String uri, char[] source, IJavaProject project) throws Exception {
-//		String[] classpathEntries = getClasspathEntries(project);
-//		String unitName = uri.substring(uri.lastIndexOf("/"));
-//		return parse(source, uri, unitName, classpathEntries);
-//	}
-//
-//	public static CompilationUnit parse(char[] source, String docURI, String unitName, String[] classpathEntries) throws Exception {
-//		ASTParser parser = ASTParser.newParser(AST.JLS11);
-//		Map<String, String> options = JavaCore.getOptions();
-//		JavaCore.setComplianceOptions(JavaCore.VERSION_11, options);
-//		parser.setCompilerOptions(options);
-//		parser.setKind(ASTParser.K_COMPILATION_UNIT);
-//		parser.setStatementsRecovery(true);
-//		parser.setBindingsRecovery(true);
-//		parser.setResolveBindings(true);
-//
-//		String[] sourceEntries = new String[] {};
-//		parser.setEnvironment(classpathEntries, sourceEntries, null, false);
-//
-//		parser.setUnitName(unitName);
-//		parser.setSource(source);
-//
-//		CompilationUnit cu = (CompilationUnit) parser.createAST(null);
-//
-//		return cu;
-//	}
-	
 	public static CompilationUnit parse2(char[] source, String docURI, String unitName, IJavaProject project) throws Exception {
 		List<Classpath> classpaths = createClasspath(getClasspathEntries(project));
 		return parse2(source, docURI, unitName, classpaths, null);
@@ -294,7 +250,7 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 			needToResolveBindings = false;
 		}
 		
-		CompilationUnit cu = CUResolver.convert(unit, source, AST.JLS11, options, needToResolveBindings, DefaultWorkingCopyOwner.PRIMARY, flags);
+		CompilationUnit cu = CUResolver.convert(unit, source, AST.JLS14, options, needToResolveBindings, DefaultWorkingCopyOwner.PRIMARY, flags);
 
 		return cu;
 	}
@@ -331,7 +287,16 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 		}
 	}
 
+	private void invalidateCuForJavaFile(String uriStr) {
+		logger.info("CU Cache: invalidate AST for {}", uriStr);
+
+		URI uri = URI.create(uriStr);
+		uriToCu.invalidate(uri);
+	}
+
 	private void invalidateProject(IJavaProject project) {
+		logger.info("CU Cache: invalidate project <{}>", project.getElementName());
+
 		Set<URI> docUris = projectToDocs.getIfPresent(project);
 		if (docUris != null) {
 			uriToCu.invalidateAll(docUris);
@@ -342,13 +307,13 @@ public final class CompilationUnitCache implements DocumentContentProvider {
 
 	@Override
 	public String fetchContent(URI uri) throws Exception {
-		if (documents != null) {
-			TextDocument document = documents.get(uri.toString());
+		if (documentService != null) {
+			TextDocument document = documentService.getLatestSnapshot(uri.toString());
 			if (document != null) {
-				return document.get(0, document.getLength());
+				return document.get();
 			}
 		}
 		return IOUtils.toString(uri);
-
 	}
+
 }

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/xml/hyperlinks/BeanRefHyperlinkProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019, 2020 Pivotal, Inc.
+ * Copyright (c) 2019, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -24,7 +24,6 @@ import org.springframework.ide.vscode.boot.java.handlers.EnhancedSymbolInformati
 import org.springframework.ide.vscode.boot.java.handlers.SymbolAddOnInformation;
 import org.springframework.ide.vscode.commons.java.IJavaProject;
 import org.springframework.ide.vscode.commons.languageserver.java.JavaProjectFinder;
-import org.springframework.ide.vscode.commons.languageserver.util.SimpleTextDocumentService;
 import org.springframework.ide.vscode.commons.util.text.TextDocument;
 
 /**
@@ -34,12 +33,10 @@ public class BeanRefHyperlinkProvider implements XMLHyperlinkProvider {
 	
 	private final JavaProjectFinder projectFinder;
 	private final SpringSymbolIndex symbolIndex;
-	private final SimpleTextDocumentService documents;
 
-	public BeanRefHyperlinkProvider(JavaProjectFinder projectFinder, SpringSymbolIndex symbolIndex, SimpleTextDocumentService documents) {
+	public BeanRefHyperlinkProvider(JavaProjectFinder projectFinder, SpringSymbolIndex symbolIndex) {
 		this.projectFinder = projectFinder;
 		this.symbolIndex = symbolIndex;
-		this.documents = documents;
 	}
 
 	@Override
@@ -47,11 +44,26 @@ public class BeanRefHyperlinkProvider implements XMLHyperlinkProvider {
 		Optional<IJavaProject> foundProject = this.projectFinder.find(doc.getId());
 		if (foundProject.isPresent()) {
 			final IJavaProject project = foundProject.get();
+			String projectLocation = project.getLocationUri() != null ? project.getLocationUri().toString() : "";
+			
+			// make sure the project and the symbol location share the same prefix "file:///"
+			// looks like project locations are containing a "file:/" only
+			if (!projectLocation.startsWith("file:///")) {
+				projectLocation = "file:///" + projectLocation.substring("file:/".length());
+			}
+			
+			// make sure that only exact project locations are matched
+			if (!projectLocation.endsWith("/")) {
+				projectLocation = projectLocation + "/";
+			}
+			
 			List<SymbolInformation> symbols = symbolIndex.getSymbols(data -> symbolsFilter(data, attributeAt.getValue())).collect(Collectors.toList());
 			if (!symbols.isEmpty()) {
 				for (SymbolInformation symbol : symbols) {
 					Location location = symbol.getLocation();
-					if (project == documents.get(location.getUri())) {
+					String uri = location.getUri();
+					
+					if (uri != null && uri.startsWith(projectLocation)) {
 						return location;
 					}
 				}
@@ -63,7 +75,7 @@ public class BeanRefHyperlinkProvider implements XMLHyperlinkProvider {
 	
 	private boolean symbolsFilter(EnhancedSymbolInformation data, String beanId) {
 		SymbolAddOnInformation[] additionalInformation = data.getAdditionalInformation();
-		if (additionalInformation != null) {
+		if (beanId != null && additionalInformation != null) {
 			for (SymbolAddOnInformation info : additionalInformation) {
 				if (info instanceof BeansSymbolAddOnInformation) {
 					return beanId.equals(((BeansSymbolAddOnInformation)info).getBeanID());

headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/quickfix/AppYamlQuickfixes.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019, 2020 Pivotal, Inc.
+ * Copyright (c) 2019, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -63,7 +63,8 @@ public class AppYamlQuickfixes {
 		DEPRECATED_PROPERTY = r.register("DEPRECATED_YAML_PROPERTY", (Object _params) -> {
 			DeprecatedPropertyData params = gson.fromJson((JsonElement)_params, DeprecatedPropertyData.class);
 			try {
-				TextDocument _doc = textDocumentService.getDocument(params.getUri());
+				TextDocument _doc = textDocumentService.getLatestSnapshot(params.getUri());
+
 				if (_doc != null) {
 					YamlDocument doc = new YamlDocument(_doc, structureProvider);
 					SNode root = doc.getStructure();

headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/java/value/test/ValueSpelExpressionValidationTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2020 Pivotal, Inc.
+ * Copyright (c) 2020, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -316,7 +316,7 @@ public class ValueSpelExpressionValidationTest {
 		server.getTextDocumentService().didOpen(openParams);
 		server.getAsync().waitForAll();
 		
-		TextDocument doc = server.getTextDocumentService().get(docUri);
+		TextDocument doc = server.getTextDocumentService().getLatestSnapshot(docUri);
 		
 		int position = content.indexOf(selectedAnnotation);
 		doc.replace(position, selectedAnnotation.length(), annotationStatementBeforeTest);

headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/java/value/test/XMLSpelExpressionValidationTest.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2020 Pivotal, Inc.
+ * Copyright (c) 2020, 2021 Pivotal, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -141,7 +141,7 @@ public class XMLSpelExpressionValidationTest {
 		server.getTextDocumentService().didOpen(openParams);
 		server.getAsync().waitForAll();
 		
-		TextDocument doc = server.getTextDocumentService().get(docUri);
+		TextDocument doc = server.getTextDocumentService().getLatestSnapshot(docUri);
 		
 		int position = content.indexOf(selectedAnnotation);
 		doc.replace(position, selectedAnnotation.length(), annotationStatementBeforeTest);