NPE error in textDocument/documentHighlight requests

[kevinh-autoserve1]

Request textDocument/documentHighlight failed.
Message: Internal error.
Code: -32603
java.util.concurrent.CompletionException: java.lang.NullPointerException: Cannot read the array length because "locations" is null
at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(Unknown Source)
at java.base/java.util.concurrent.CompletableFuture.completeThrowable(Unknown Source)
at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
at java.base/java.util.concurrent.CompletableFuture$Completion.exec(Unknown Source)
at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Cannot read the array length because "locations" is null
at org.eclipse.jdt.ls.core.internal.handlers.DocumentHighlightHandler.convertToHighlights(DocumentHighlightHandler.java:131)
at org.eclipse.jdt.ls.core.internal.handlers.DocumentHighlightHandler.findHighlights(DocumentHighlightHandler.java:100)
at org.eclipse.jdt.ls.core.internal.handlers.DocumentHighlightHandler.documentHighlight(DocumentHighlightHandler.java:68)
at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$13(JDTLanguageServer.java:679)
at org.eclipse.jdt.ls.core.internal.BaseJDTLanguageServer.lambda$0(BaseJDTLanguageServer.java:79)
... 7 more

Environment

• Operating System: Windows and WSL (Ubuntu)
• JDK version: 17
• Visual Studio Code version: 1.75.1
• Java extension version: 1.14.0

Steps To Reproduce

1. Open Java project
2. After several uses of language server, it eventually starts crashing and no code completions or symbol lookups function. Requires restart, which eventually just starts crashing again.

[Please attach a sample project reproducing the error]
Please attach logs

Current Result

Expected Result

Additional Informations

[jdneo]

We do have a potential NPE at

at org.eclipse.jdt.ls.core.internal.handlers.DocumentHighlightHandler.convertToHighlights(DocumentHighlightHandler.java:131)

But I have no idea if this could 'crash' the Java language server.

Meanwhile, there are several complains saying that the extension stops working for some reason these days.

#2941
#1765 (comment)

@kevinh-autoserve1 It would be helpful if a sample project with detailed steps could provide.