The plugin has an executable option which can refer to the java executable. Per it uses the system default, which apparently is different between my bash and the shell that eclipse uses. If I hard code the correct path, it works correctly.
But a hardcoded path is not okay, so I'm going to try and see if I can make a PR so the plugin use the same java as the compiler. That would make it less unpredictable. And possibly use toolchains, since I now know it exists :-)
