Fail to compile Java 21 unnamed class

[testforstephen]

Try Java 21 feature in the latest language server version, it fails to compile the Java 21 unnamed class.

UnnamedTest.java

String greeting() { return "Hello, World!"; }

void main() {
    System.out.println(greeting());
}

JavaBuilder error log:

!ENTRY org.eclipse.jdt.core 4 4 2024-03-06 14:25:39.664
!MESSAGE JavaBuilder handling CoreException
!STACK 1
org.eclipse.core.internal.resources.ResourceException: < is an invalid character in resource name '<unnamed_class$UnnamedTest>.class'.
	at org.eclipse.core.internal.resources.Resource.checkValidPath(Resource.java:470)
	at org.eclipse.core.internal.resources.File.create(File.java:125)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.writeClassFileContents(AbstractImageBuilder.java:930)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.writeClassFile(AbstractImageBuilder.java:906)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.acceptResult(AbstractImageBuilder.java:217)
	at org.eclipse.jdt.internal.compiler.Compiler.processCompiledUnits(Compiler.java:614)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:474)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:425)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:411)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.compile(BatchImageBuilder.java:214)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:342)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.build(BatchImageBuilder.java:79)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.buildAll(JavaBuilder.java:286)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:192)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1077)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:296)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:352)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:441)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:444)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:555)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:503)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:585)
	at org.eclipse.core.internal.resources.Workspace.buildInternal(Workspace.java:594)
	at org.eclipse.core.internal.resources.Workspace.build(Workspace.java:483)
	at org.eclipse.jdt.ls.core.internal.handlers.BuildWorkspaceHandler.buildWorkspace(BuildWorkspaceHandler.java:65)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$27(JDTLanguageServer.java:988)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$60(JDTLanguageServer.java:1223)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.exec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
!SUBENTRY 1 org.eclipse.core.resources 4 77 2024-03-06 14:25:39.664
!MESSAGE < is an invalid character in resource name '<unnamed_class$UnnamedTest>.class'.

[fbricon]

I believe this will be fixed by eclipse-jdtls/eclipse-jdt-core-incubator#102. @datho7561 ?

[rgrunber]

This should be fixed now. Feel free to close if it's confirmed.

[fbricon]

microsoft/vscode-java-debug#1444 was closed so that's confirmation it worked.