Fix for "no delegatecommandhandler for vscode java resolvemainmethod" error when using Open VSX

I was setting up Antigravity for Java and ran into a problem I want to share in case others encounter it.

After installing JDK 17 from Oracle and the "Extension Pack for Java" from the default Open VSX registry, I encountered an error while trying to debug: "no delegatecommandhandler for vscode java resolvemainmethod".

It took hours of troubleshooting to realize the cause: In Open VSX, the "Language Support for Java by Red Hat" extension was version 1.12.0, which does not support JDK 17.

To fix this, I had to change the default marketplace to the official Visual Studio Marketplace by adding these URLs to my settings and then installing the newest version of the extension from there:

• Marketplace Item URL: https://marketplace.visualstudio.com/items
• Marketplace Gallery URL: https://marketplace.visualstudio.com/_apis/public/gallery

I'm not sure why Open VSX has such an old version of Language Support for Java as the default, but I'm glad I finally found the real problem. Hopefully, this saves someone else a few hours of debugging!