SourceSet.getCompileClasspath() returns null

[graetzer]

I tried to look for a similar issue, but could not find any.

We have a large propriatery gradle project, with many different sub-modules. I am unable to open it with this plugin, due to the following exceptions in the java language server:

java.lang.NullPointerException: Cannot invoke "ch.epfl.scala.bsp4j.TaskId.getId()" because the return value of "ch.epfl.scala.bsp4j.LogMessageParams.getTask()" is null
	at com.microsoft.gradle.bs.importer.GradleBuildClient.onBuildLogMessage(GradleBuildClient.java:89)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.lambda$recursiveFindRpcMethods$0(GenericEndpoint.java:65)
	at org.eclipse.lsp4j.jsonrpc.services.GenericEndpoint.notify(GenericEndpoint.java:160)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleNotification(RemoteEndpoint.java:231)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.consume(RemoteEndpoint.java:198)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.handleMessage(StreamMessageProducer.java:185)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:97)
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:114)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

[Error - 14:08:44] 05.11.2025, 14:08:44 Initialization failed 
java.util.concurrent.CompletionException: org.eclipse.lsp4j.jsonrpc.ResponseErrorException: Cannot invoke "org.gradle.api.file.FileCollection.getFiles()" because the return value of "org.gradle.api.tasks.SourceSet.getCompileClasspath()" is null
	at java.base/java.util.concurrent.CompletableFuture.reportJoin(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture.join(Unknown Source)
	at com.microsoft.gradle.bs.importer.Utils.getBuildTargetsMappedByProjectPath(Utils.java:55)
	at com.microsoft.gradle.bs.importer.GradleBuildServerProjectImporter.importProjects(GradleBuildServerProjectImporter.java:324)
	at com.microsoft.gradle.bs.importer.GradleBuildServerProjectImporter.importToWorkspace(GradleBuildServerProjectImporter.java:228)
	at org.eclipse.jdt.ls.core.internal.managers.ProjectsManager.importProjects(ProjectsManager.java:164)
	at org.eclipse.jdt.ls.core.internal.managers.ProjectsManager.initializeProjects(ProjectsManager.java:126)
	at org.eclipse.jdt.ls.core.internal.handlers.InitHandler$1.runInWorkspace(InitHandler.java:263)
	at org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:43)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
Caused by: org.eclipse.lsp4j.jsonrpc.ResponseErrorException: Cannot invoke "org.gradle.api.file.FileCollection.getFiles()" because the return value of "org.gradle.api.tasks.SourceSet.getCompileClasspath()" is null
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.handleResponse(RemoteEndpoint.java:220)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.consume(RemoteEndpoint.java:204)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.handleMessage(StreamMessageProducer.java:185)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:97)
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:114)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)