title: Code Completion stopped working for "Java Extension Pack"
body: <p>I am currently working on a Java project using the <code>Java Extension Pack</code> for VS Code. Thus plugin has been working for three weeks and now the auto completion has decided to stop for no reason.</p>
  
  <p>Looking in the 'output' tab, I can see the following errors: </p>
  
  <pre><code>[Error - 1:56:31 PM] 23-Dec-2019 13:56:31 Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:56:31 PM] 23-Dec-2019 13:56:31 Error in calling delegate command handler
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:56:32 PM] 23-Dec-2019 13:56:32 Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:56:32 PM] 23-Dec-2019 13:56:32 Error in calling delegate command handler
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:57:37 PM] 23-Dec-2019 13:57:37 Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:57:37 PM] 23-Dec-2019 13:57:37 Error in calling delegate command handler
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:57:37 PM] 23-Dec-2019 13:57:37 Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:57:37 PM] 23-Dec-2019 13:57:37 Error in calling delegate command handler
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:57:38 PM] 23-Dec-2019 13:57:38 Problems occurred when invoking code from plug-in: "org.eclipse.jdt.ls.core".
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  
  [Error - 1:57:38 PM] 23-Dec-2019 13:57:38 Error in calling delegate command handler
  org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
  java.lang.NoSuchMethodError: org.eclipse.jdt.ls.core.internal.contentassist.CompletionProposalRequestor.&lt;init&gt;(Lorg/eclipse/jdt/core/ICompilationUnit;I)V
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.initializeRequestor(CompletionProvider.java:133)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.computeContentAssist(CompletionProvider.java:89)
      at com.microsoft.jdtls.intellicode.core.CompletionProvider.provideCompletionItems(CompletionProvider.java:60)
      at com.microsoft.jdtls.intellicode.core.CommandHandler.executeCommand(CommandHandler.java:57)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:215)
      at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
      at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:205)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$3(JDTLanguageServer.java:472)
      at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$48(JDTLanguageServer.java:963)
      at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
      at java.util.concurrent.CompletableFuture$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)
  </code></pre>
  
  <p>What's going on here and is there anything I can do to fix it?</p>