VSCode doesn't show JDK Java source files when debugging JDK itself

まず、レポートに示されている launch.json javaExec と classPaths、および java.configuration.runtimes 設定から始め、Java デバッガーが JDK クラスのソースをどのように選択するかを追跡します。記載されている OpenJDK Main.java の変更で問題を再現し、デバッグ時に互換性のないクラスビューではなく、変更後の Java ソースが表示されることを確認します。

I'm building and debugging the latest version of OpenJDK on Windows 11. I'd like to debug it with VSCode, however I met the following problem:

I made changes in JDK Java sources (say added System.out.println("Hello") in src\jdk.javadoc\share\classes\jdk\javadoc\internal\tool\Main.java) and built JDK using JDK19 as boot JDK. I run my Java test using my freshly built JDK. It successfully starts and prints "Hello". Then I set a breakpoint at the line after my change in VSCode, and run the test under VSCode debugger. It starts, prints "Hello", and stops on my breakpoint, and shows source code, but I can't see my changes, because VSCode loaded jdk.javadoc\jdk.javadoc.internal.tool\Main.class instead of the changed Main.java.

I suppose, the class file was taken from java.configuration.runtimes, but I have no idea how can I force VSCode to load changed sources while debugging. Although VSCode is still able to show and debug my own Java-files, and, moreover, modified native JDK code (C/C++ sources), not Java.

BTW I've got the following pop-up message when debugger starts: "The compiled classes are not compatible with the runtime JDK."

Environment

• Operating System: Windows 11
• JDK version: 19
• Visual Studio Code version: 1.74.3
• Extension pack for Java: 0.25.7
• Java Debugger extension version: 0.47.0

Steps To Reproduce

1. Clone openjdk repository (https://github.com/openjdk/jdk.git) and build it
2. Make a little change in JDK's Java source file, e.g. add System.out.println("Hello") in src\jdk.javadoc\share\classes\jdk\javadoc\internal\tool\Main.java
3. Set a breakpoint at the changed line and try to debug it with VSCode

Current Result

VSCode stops at the breakpoint, loads *.class file, which doesn't contain my changes.

Expected Result

VSCode stops at the breakpoint, loads changed *.java files and shows them in debugger.

Additional Informations

My setting.json:

"java.configuration.runtimes": [
    {
        "default": true,
        "name": "JavaSE-19",
        "path": "c:\\work\\jdk19",
    }
],

My launch.json:

{
    "type": "java",
    "name": "(java) Debug",
    "request": "launch",
    "cwd": "${workspaceFolder}",
    "mainClass": "jdk.javadoc.internal.tool.Main",
    "javaExec": "${workspaceFolder}\\build\\windows-x86_64-server-fastdebug\\jdk\\bin\\java.exe",
    "classPaths": [
        "${workspaceFolder}/build/windows-x86_64-server-fastdebug/images/jdk/lib/jrt-fs.jar",
    ],
},