Extension hangs with org.eclipse.jface.text.BadLocationException

Pretty often when I am refactoring my code and there (one or two files contain pretty broken code) - extension hangs and all it's features stop working.

Restarting VSCode fixes the issue.

My project is super simple (5 classes), has rudimentary pom.xml.

Output window for Language Support for Java shows this error:

[Error - 9:07:53 PM] Aug 1, 2018 9:07:02 PM 
null
org.eclipse.jface.text.BadLocationException
	at org.eclipse.jface.text.TreeLineTracker.fail(TreeLineTracker.java:1051)
	at org.eclipse.jface.text.TreeLineTracker.lineByOffset(TreeLineTracker.java:265)
	at org.eclipse.jface.text.TreeLineTracker.getLineNumberOfOffset(TreeLineTracker.java:1119)
	at org.eclipse.jface.text.AbstractLineTracker.getLineNumberOfOffset(AbstractLineTracker.java:151)
	at org.eclipse.jface.text.AbstractDocument.getLineOfOffset(AbstractDocument.java:868)
	at org.eclipse.core.internal.filebuffers.SynchronizableDocument.getLineOfOffset(SynchronizableDocument.java:331)
	at org.eclipse.jdt.ls.core.internal.handlers.JsonRpcHelpers.toLine(JsonRpcHelpers.java:60)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.toRange(JDTUtils.java:466)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.toLocation(JDTUtils.java:380)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.toLocation(JDTUtils.java:342)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentSymbolHandler.collectChildren(DocumentSymbolHandler.java:75)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentSymbolHandler.collectChildren(DocumentSymbolHandler.java:68)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentSymbolHandler.getOutline(DocumentSymbolHandler.java:52)
	at org.eclipse.jdt.ls.core.internal.handlers.DocumentSymbolHandler.documentSymbol(DocumentSymbolHandler.java:44)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$12(JDTLanguageServer.java:532)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$23(JDTLanguageServer.java:732)
	at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
	at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
	at java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:443)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

Same error and stack dump can be found in the log that I open with "Java: Open Java Language Server log file".

(related?) Dev Tools console log contains quite a lot copies of this warning:

 WARN Error: listener failed
    at workbench.main.js:sourcemap:4061
    at Object.g [as _notify] (workbench.main.js:sourcemap:150)
    at Object.enter (workbench.main.js:sourcemap:154)
    at n.Class.derive._oncancel._run (workbench.main.js:sourcemap:155)
    at n.Class.derive._oncancel._completed (workbench.main.js:sourcemap:155)
    at e.resolveOk (workbench.main.js:sourcemap:3060)
    at e._receiveReply (workbench.main.js:sourcemap:3127)
    at e._receiveOneMessage (workbench.main.js:sourcemap:3126)
    at workbench.main.js:sourcemap:3125
    at workbench.main.js:sourcemap:3128
    at e.fire (workbench.main.js:sourcemap:171)
    at c (workbench.main.js:sourcemap:302)
    at Socket.<anonymous> (workbench.main.js:sourcemap:303)
    at emitOne (events.js:96)
    at Socket.emit (events.js:191)
    at readableAddChunk (_stream_readable.js:178)
    at Socket.Readable.push (_stream_readable.js:136)
    at Pipe.onread (net.js:560)

I was experiencing the same issue with the previous version of the extension.

When extension hangs, VSCode status bar usually says "Validating document - 0%"

Environment

• Operating System: Win10 v1803
• JDK version: 1.8.0_181
• Visual Studio Code version: 1.25.1
• Java extension version: 0.29.0

Steps To Reproduce

Not quite sure about the pattern or repro yet, but happens like every hour (=pretty often).

まず DocumentSymbolHandler、JDTUtils、JsonRpcHelpers のスタックトレースのエントリから始め、壊れた Java ファイルを使ってハングを再現し、Java Language Server のログを調べます。ドキュメントの検証と拡張機能が BadLocationException によるハングなしで動作し続ければ、問題は解決しています。