Debugger for Java (Preview) is not working. #617

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1. github-actions commented on Dec 14, 2025

   

   github-actionsbot

   on Dec 14, 2025 – with GitHub Actions

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   Hi mozhuanzuojing, I'm an AI Support assistant here to help with your issue. While the team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

   Here are a few things to try:

   • Switch off the pre-release build of the Java debugger and use the latest stable version: click Switch to Release Version on the Debugger for Java extension page.
   • Make sure you have JDK 11+ installed and VS Code is pointing at it. The error “Java 11 or more recent is required…” means you’re on Java 8. Either install a newer JDK or set:

     "java.home": "/path/to/your/jdk-17"

     in your settings.json and reload VS Code.
   • Add an explicit launch configuration so VS Code knows how to start your app. In .vscode/launch.json:

     {
       "version": "0.2.0",
       "configurations": [
         {
           "type": "java",
           "name": "Debug Current File",
           "request": "launch",
           "mainClass": "${file}"
         }
       ]
     }

   Other references worth checking:

   • URGENT- “Java 11 or more recent is required to run…” — installing a JDK 11+ fixes the “Java 11…” popup (and debugger activation).
     URGENT- "Java 11 or more recent is required to run. Please download and install a recent JDK" vscode-java-debug#852

   Other references with low confidence

   • Unable to Debug On VS Code — issues with JDT LS/Decompiler; may shed light if you see "Unable to load IDecompiler class" in logs.
     Unable to Debug On Vscode  vscode-java-debug#1385
   • Getting java.lang.UnsupportedClassVersionError when debugging tests — only applies if you’re debugging JUnit with an older JVM.
     Getting java.lang.UnsupportedClassVersionError in debug console when trying to run or debug any test vscode-java-test#1194

   The team will respond to your issue shortly. I hope these suggestions are helpful in the meantime. If this comment helped you, please give it a 👍. If the suggestion was not helpful or incorrect, please give it a 👎. Your feedback helps us improve!
2. github-actions

   added

   ai-triaged

   bug

   on Dec 14, 2025
3. chagong commented on Dec 15, 2025

   

   Changyong Gong (chagong)

   on Dec 15, 2025

   Contributor

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   Hi mozhuanzuojing, can you briefly describe in what way it's not working?
4. Changyong Gong (chagong)

   added

   needs more info

   on Dec 15, 2025
5. mozhuanzuojing commented on Dec 15, 2025

   

   mozhuanzuojing

   on Dec 15, 2025

   ContributorAuthor

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   Changyong Gong (@chagong) Exception status information is as follows.

   

   After starting the debug process, an error occurs in the log output.

   [Trace - 4:59:44 PM] Received notification 'window/logMessage'.
   [Error - 4:59:44 PM] Dec 15, 2025, 4:59:44 PM [error response][stackTrace]: Cannot read field "path" because "lspFrame.source" is null
   java.lang.NullPointerException: Cannot read field "path" because "lspFrame.source" is null
   	at com.microsoft.java.debug.core.adapter.handler.StackTraceRequestHandler.handle(StackTraceRequestHandler.java:118)
   	at com.microsoft.java.debug.core.adapter.DebugAdapter.lambda$dispatchRequest$0(DebugAdapter.java:94)
   	at java.base/java.util.concurrent.CompletableFuture.uniComposeStage(Unknown Source)
   	at java.base/java.util.concurrent.CompletableFuture.thenCompose(Unknown Source)
   	at com.microsoft.java.debug.core.adapter.DebugAdapter.dispatchRequest(DebugAdapter.java:93)
   	at com.microsoft.java.debug.core.adapter.ProtocolServer.dispatchRequest(ProtocolServer.java:132)
   	at com.microsoft.java.debug.core.protocol.AbstractProtocolServer.lambda$new$0(AbstractProtocolServer.java:81)
   	at io.reactivex.internal.observers.LambdaObserver.onNext(LambdaObserver.java:63)
   	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.drainNormal(ObservableObserveOn.java:201)
   	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.run(ObservableObserveOn.java:255)
   	at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:66)
   	at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:57)
   	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
   	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
   	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
   	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
   	at java.base/java.lang.Thread.run(Unknown Source)
   
   [Trace - 4:59:44 PM] Received notification 'telemetry/event'.
   Dec 15, 2025 4:59:44 PM com.microsoft.java.debug.core.adapter.ProtocolServer lambda$dispatchRequest$1
   SEVERE: [error response][stackTrace]: Cannot read field "path" because "lspFrame.source" is null
   java.lang.NullPointerException: Cannot read field "path" because "lspFrame.source" is null
   	at com.microsoft.java.debug.core.adapter.handler.StackTraceRequestHandler.handle(StackTraceRequestHandler.java:118)
   	at com.microsoft.java.debug.core.adapter.DebugAdapter.lambda$dispatchRequest$0(DebugAdapter.java:94)
   	at java.base/java.util.concurrent.CompletableFuture.uniComposeStage(Unknown Source)
   	at java.base/java.util.concurrent.CompletableFuture.thenCompose(Unknown Source)
   	at com.microsoft.java.debug.core.adapter.DebugAdapter.dispatchRequest(DebugAdapter.java:93)
   	at com.microsoft.java.debug.core.adapter.ProtocolServer.dispatchRequest(ProtocolServer.java:132)
   	at com.microsoft.java.debug.core.protocol.AbstractProtocolServer.lambda$new$0(AbstractProtocolServer.java:81)
   	at io.reactivex.internal.observers.LambdaObserver.onNext(LambdaObserver.java:63)
   	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.drainNormal(ObservableObserveOn.java:201)
   	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.run(ObservableObserveOn.java:255)
   	at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:66)
   	at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:57)
   	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
   	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
   	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
   	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
   	at java.base/java.lang.Thread.run(Unknown Source)
   
   Dec 15, 2025 4:59:44 PM com.microsoft.java.debug.core.UsageDataSession recordResponse
   WARNING: abnormal response
   

   env

   

   👀React with 👀1Reacted by Changyong Gong
6. Changyong Gong (chagong)

   self-assigned this

   on Dec 16, 2025
7. Changyong Gong (chagong)

   closed this as completedin #618on Dec 16, 2025
8. chagong commented on Dec 16, 2025

   

   Changyong Gong (chagong)

   on Dec 16, 2025

   Contributor

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   mozhuanzuojing I just made a prerelease version 0.58.2025121609, can you try if it solves the problem?
9. mozhuanzuojing commented on Dec 16, 2025

   

   mozhuanzuojing

   on Dec 16, 2025

   ContributorAuthor

   More actions

   Changyong Gong (@chagong) Great, thank you! The debug tool is working fine now in the latest prerelease.

   👍React with 👍2Reacted by Changyong Gong and mozhuanzuojing