Empty src/main folder appears when Show Non-Java Resources is enabled

[wenytang-ms]

Description

When Show Non-Java Resources is enabled, the Java Projects view can display an empty physical folder hierarchy such as src/main alongside the actual Java package roots (src/main/java and src/main/resources).

This was reported as part of #1044. This issue tracks only the empty src/main hierarchy, which is a rendering/data-model bug. The visibility of build output such as target is a separate filtering-policy question.

Root cause

The project children returned by java.getPackageData combine Java classpath roots with IJavaProject.getNonJavaResources().

The physical src folder can therefore be emitted as a non-Java folder even though its descendants are represented separately as Java package roots. When that folder is expanded, Java elements such as src/main/java and src/main/resources are filtered from its non-Java children, leaving an empty src/main hierarchy in the tree.

Relevant implementation:

• jdtls.ext/.../PackageCommand.java#getProjectChildren
• jdtls.ext/.../parser/ResourceSet.java
• jdtls.ext/.../parser/JavaResourceVisitor.java

Expected behavior

Enabling Show Non-Java Resources should continue to show actual non-Java files, such as YAML and XML resources, but should not display ancestor folders that have no visible children because their content is already represented by Java package roots.

Acceptance criteria

• Non-Java resource files remain visible.
• Empty duplicate ancestor hierarchies such as src/main are not shown.
• Existing Java source and resource package roots remain visible and functional.
• Add regression coverage for the returned project tree and an E2E UI scenario if practical.

Related: #1044

[github-actions]

Hi wenyt (@wenytang-ms), 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.

Proposed fix

• In PackageCommand.java#getProjectChildren, skip non-Java folders that are only ancestors of Java roots and contain no actual non-Java files:

  for (IFolder folder : nonJavaRootFolders) {
      boolean isAncestorOfJavaRoot = javaRoots.stream()
          .anyMatch(root -> folder.getFullPath().isPrefixOf(root));
      boolean hasResources = resourceSet.listNonJavaChildren(folder).anyMatch(child -> !child.isFolder());
      if (isAncestorOfJavaRoot && !hasResources) {
          continue;
      }
      // … add folder to tree
  }

• In ResourceSet.java/JavaResourceVisitor.java, similarly filter out empty ancestor hierarchies before adding to the model.

• Add unit tests for java.getPackageData to assert that src/main is not emitted when it has no direct non-Java files, and an E2E UI test.

References

• Root report: Issue Java Projects view displays redundant empty folders when "Show Non-Java Resources" is enabled #1044 (tracks general non-Java resources rendering)

Other references with low confidence

• Show non Java Projects in the Java Projects explorer
  Discusses showing non-Java projects/resources in the Java Projects view (may help with filtering logic).
  URL: feat: Display non-java resources in the Project explorer #730

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