Discovering main class does not work with arguments

[asmodeus812]

Hi i am attempting to call the vscode.java.resolveMainClass with a single argument (the arguments param being array with one entry, the uri) being the uri to a file which is part of a project to which jdtls has been attached to with the java-debug extension enabled. If i try to do that, i get empty response, no errors seemingly. If i pass no uri, just call the command to resolve the main classes it returns fine, the issue here is that i have single jdtls instance which has multiple workspaces / projects attached to it, and so i would like to use the argument to narrow down the result to only the current workspace / context by passing the uri. According to the implementation, it is supposed to handle file uris passed as the first and only argument to this method to use it to resolve the result in ResolveMainClassHandler

[ERROR][2023-05-22 16:04:05] ...lsp/handlers.lua:535	"May 22, 2023, 4:04:05 PM Error in calling delegate command handler\nclass java.lang.String cannot be cast to class java.util.ArrayList (java.lang.String and java.util.ArrayList are in module java.base of loader 'bootstrap')\njava.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.ArrayList (java.lang.String and java.util.ArrayList are in module java.base of loader 'bootstrap')\n\tat org.eclipse.jdt.ls.core.internal.JDTDelegateCommandHandler.executeCommand(JDTDelegateCommandHandler.java:94)\n\tat org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:230)\n\tat org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)\n\tat org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler.executeCommand(WorkspaceExecuteCommandHandler.java:220)\n\tat org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$4(JDTLanguageServer.java:585)\n\tat org.eclipse.jdt.ls.core.internal.BaseJDTLanguageServer.lambda$0(BaseJDTLanguageServer.java:87)\n\tat java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:646)\n\tat java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:483)\n\tat java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387)\n\tat java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1312)\n\tat java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1843)\n\tat java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1808)\n\tat java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:188)\n"

Here is what is being sent

[DEBUG][2023-05-22 16:13:01] .../vim/lsp/rpc.lua:284	"rpc.send"	{  id = 6,  jsonrpc = "2.0",  method = "workspace/executeCommand",  params = {    arguments = { "file:///home/asmodeus/.projects/javahehe/src/main/java/com/mycompany/app/App17.java" },    command = "vscode.java.resolveMainClass"  }}

[github-actions]

Hi Svetlozar Iliev (@asmodeus812), 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.

Solution

• The JDTLS handler expects the first entry in arguments to be a list, not a string. Wrap your URI in an extra array. For example:

  {
    "command": "vscode.java.resolveMainClass",
    "arguments": [
      [ "file:///home/asmodeus/.projects/javahehe/src/main/java/com/mycompany/app/App17.java" ]
    ]
  }

  This way, arguments.get(0) will be a list (ArrayList) rather than a raw string.

References

• Error when executeCommand 'vscode.java.resolveClasspath': shows the same pattern (first argument must be a list). See discussion and code at
  Error when executeCommand 'vscode.java.resolveClasspath' redhat-developer/vscode-java#2736 (comment)
  and handler implementation:

  java-debug/com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/ResolveClasspathsHandler.java

  Line 71 in f5ab690

  public String[][] resolveClasspaths(List<Object> arguments) throws Exception {

Other references with low confidence

• No JAVA PACKAGES explorer sidebar on symlink folders: unrelated to resolveMainClass, but shows another workspace/executeCommand example for java.project.list returning an array: No JAVA PACKAGES explorer sidebar on symlink folders vscode-java-dependency#77 (comment)

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!