.java is not on the class path of project A, only syntax errors are reported

[AnqiHuangQiQi]

This is from one of the Java files which is covered by Bazel targets listed in .bazelproject.

This is from the Open All Java Logs in Vscode.

From OUTPUT window, I saw "Bazel build with aspects".

Also saw correct class paths from the OUTPUT.

Result: {
    "projectRoot": "file:/myjava",
    "classpaths": [

My Java project structure

Root
-WORKSPACE
-java/B/C: Bazel BUILD file
-java/B/D: Bazel BUILD file

For .bazelproject, I have tried

directories:
  java 
//or java/B/C

derive_targets_from_directories: true

directories:
  java 
//or java/B/C

derive_targets_from_directories: false

targets:
  //java/B/C:all

Also tried updating the .classpath file by adding some

<classpathentry kind="src"...

None of these could solve the issue.

[AnqiHuangQiQi]

Ok. I tried a Simple & Clean Sample Bazel Java project from Bazel official https://bazel.build/start/java .
Repo: https://github.com/bazelbuild/examples/tree/main/java-tutorial
Got exact same error "is not on the classpath of project".

[AnqiHuangQiQi]

@guw please take a look. Thanks ahead!

[guw]

Are you on the latest pre-release?

[AnqiHuangQiQi]

Thanks for the reply @guw

I am using the latest version.

It says "Switch to Release Version". It means I'm on Pre-release version, right?

And plus, I have run bazel-vscode-java master branch locally to run as the extension, which got the exact same error.

[guw]

I am unable to reproduce in Eclipse. Thus, it must be something the JDTLS does differently. I will try to debug this next.

[AnqiHuangQiQi]

Thank you!

I found this exact line of code from eclipse-jdtls which generated the above error message and tried to find the reason.
But not sure what's going on with the ICompilationUnit.

[guw]

I wonder if it is because of der resource type. We are using linked folders for such a setup with the individual targets.

[AnqiHuangQiQi]

Sorry. I wish to understand it better so that I could help solving problems.
I'm generally curious how Bazel-Vscode-Java/Bazel-eclipse feed the Redhat-Java-Extension/Java Language Server.

It looks like eclipse jdtls builds some JavaProject/JavaElement/JavaModel/CompilationUnit structure.
But how does it pick up the class paths we got from Bazel-eclipse?

From this .eclipse/projects view, the .class files look great.
But linked-src are all empty. Is this expected?

[AnqiHuangQiQi]

I setup the Vscode-Java/EclipseJdtls running locally and set some breakpoints.

And copied the ICompilationUnit.getJavaProject() value.

Runner target is ON class path.

ProjectRunner target is NOT on class path.

Runner.java is within the same directory as its BUILD file.

The ProjectRunner.java is within src/main/java/com/example.
But the BUILD file is out of the src/ directory.

[guw]

Quick update. I got the examples building in Eclipse. I noticed the aspects weren't working properly with latest Bazel 8.1.1 version. Thus, I decided to rework them. PR is here.

[guw]

@AnqiHuangQiQi with the PR pulled and build locally I am able to get the example running in a self-hosted VS Code.

#144

[AnqiHuangQiQi]

Thank you so much for the fix!!! @guw

It works for me too!!!

I pulled your branch from your PRs
https://github.com/salesforce/bazel-vscode-java/pull/144/files
salesforce/bazel-eclipse#515

./mvnw clean verify succeed in Bazel-eclipse

npm run build succeed in Bazel-vscode-java

Nice linked!!

[AnqiHuangQiQi]

Ugh.... It's still not working on my own Java project...

I updated the Vscode-java to pre-release version as well.
But still got "is not on the class path of project"...

The intelliijaspect and projects look so good

[guw]

How does the Java Projects view look?

For your own project ... if it looks more like a Maven project (with src/mainjava and glob **/*.java) then the project-per-package strategy might be a better fit.

[AnqiHuangQiQi]

You are right.
I'm using glob(["*.java"]).

My project looks like this:

Root
-WORKSPACE
-BUILD file
-java/B/C: Bazel BUILD file  - glob(["*.java"])
**-java/B/D**: Bazel BUILD file - glob(["*.java"])
**-java/B/D**/E: Bazel BUILD file - glob(["*.java"])

target C could depend on target D.
target D's dependencies include target E.

Here is the Java Projects View

And I tried this in my .bazelproject

target_provisioning_strategy:
  project-per-package

Ok I did a few more tests to get a stable result.
I must run Vscode-Java on Pre-release version. Otherwise, Bazel-eclipse won't kick-in.
And Bazel-ecipse/Bazel-vscode-java are both from your PR.

I manually clean up any existing bazel-* folders.
Monitor logs got:

com.microsoft.java.debug.core.DebugException: Failed to resolve main method codeLens: <project root> [in java.B.C] is not on its project's build path
	at com.microsoft.java.debug.plugin.internal.ResolveMainMethodHandler.resolveMainMethods(ResolveMainMethodHandler.java:80)
	at com.microsoft.java.debug.plugin.internal.JavaDebugDelegateCommandHandler.executeCommand(JavaDebugDelegateCommandHandler.java:80)
	at org.eclipse.jdt.ls.core.internal.handlers.WorkspaceExecuteCommandHandler$1.run(WorkspaceExecuteCommandHandler.java:230)

Caused by: Java Model Exception: Error in Java Model (code 1006): <project root> [in java.B.C] is not on its project's build path
	at org.eclipse.jdt.internal.core.JavaElement.newJavaModelException(JavaElement.java:556)
	at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:238)
	at org.eclipse.jdt.internal.core.Openable.openAncestors(Openable.java:512)

In java file editor see this

After "Clean Java Language Server Workspace", and "initialization job finished",
I can see /bazel-bin contains the related jar files.

I suspect Vscode-Java extension has problem collection the class path info built by Bazel-eclipse.
I wish to be able to find the root cause myself too. If you have any clues, especially how Bazel-eclipse could feed class paths to Vscode-java/EclipseJL. Please throw me some links or point me to the related codes. ;)
I spent some time to read the code. Basically got the idea that Vscode extension will call Language Server Commands.
And Bazel-eclipse has defined those commands. And using extension points to extend eclipse jdtls.
But still couldn't find how the computed class paths are served to Vscode.