I'm trying to remotely debug a Java web application running on Tomcat 7 using VS Code. The debugger successfully attaches to the remote instance and catches breakpoints in the call stack, but the source code/debugging symbols do not load.

My Setup:

Java version : java 8.0.352-zulu

Remote machine: Running Tomcat 7 with JPDA enabled (port 8000)

Local machine: macOS with VS Code and an SSH tunnel for debugging

Build tool: maven 3.8.1

IDE : VS Code v1.96.4

Debugging configuration: VS Code with Debugger for Java extension v0.58.1

Steps Taken So Far:

1- Ensured debug symbols are included in the compiled classes:

<build>
    <plugins>
        <plugin>
            <groupId>.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <debug>true</debug>
                <debugLevel>lines,vars,source</debugLevel>
            </configuration>
        </plugin>
    </plugins>
</build>

2- Enabled remote debugging on Tomcat (on the remote machine):

$ export JPDA_OPTS="-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=8000"
$ su - user001 -c "$CATALINA_HOME/bin/catalina.sh jpda run"

3- Opened an SSH tunnel to forward the remote debug port:

% ssh -L 8000:localhost:8000 user001@remote-server-ip

4- Configured VS Code (.vscode/launch.json):

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "java",
      "request": "attach",
      "name": "Attach to Local Tunnel",
      "hostName": "localhost",
      "port": 8000,
      "sourcePaths": [
        "/absolute/path/to/my/source/code/src/main/java"
      ]
    }
  ]
}

5- Verified the compiled .class files contain debug symbols (on the remote server):

$ javap -v $CATALINA_HOME/webapps/myapp/WEB-INF/classes/com/myapp/reporting/ReportServiceImpl.class | grep "LineNumberTable"

✅ Output confirms LineNumberTable exists.

6- Selected "Attach to Local Tunnel" in VS Code's "Run and Debug panel" and then Started Debugging (▶️).

Issue:

The debugger connects successfully and breakpoints trigger, but the corresponding source file is not loaded in VS Code.

Things I Tried But Didn't Work:

• Restarted VS Code and deleted .vscode settings and added a new clean .vscode/launch.json file.

• Rebuilt the web application and re-deployed it to Tomcat (with debug symbols included).

• Used $ netstat -tulnp | grep 8000 to confirm the remote port is open.

• Used % nc -vz localhost 8000 to verify the SSH tunnel is working on my end.

Question:

Why is VS Code unable to load the correct source file even when breakpoints are hit?

How can I force VS Code to map the source files correctly when remote debugging my Java web application?

Any help or suggestions would be greatly appreciated!