Enable javac-based compilation

[fbricon]

Requires building eclipse.jdt.ls against dom-with-javac branch of the JDT fork
Requires running with Java 23 at the moment.

First build the server jars with:

npm run build-server

then generate the vsix with:

npx @vscode/vsce package

Enable with "java.jdt.ls.javac.enabled":"on" in vscode settings

You can enable the more experimental DOM-based completion with "java.completion.engine": "dom":

[fbricon]

Daily vscode-javac builds are available from https://github.com/fbricon/vscode-java/releases/tag/javac-prototype

[viswatejan]

I wanted to try Javac and DOM but I was getting the following error.

!ENTRY org.eclipse.jdt.core 4 0 2024-11-05 13:28:32.326
!MESSAGE Internal failure while parsing or converting AST for unit /helloworld-service/src/main/java/com/hello/HelloWorld.java

!ENTRY org.eclipse.jdt.core 4 0 2024-11-05 13:28:32.333
!MESSAGE startPos = -1 and length is 3.
This breaks the rule that length must be 0 if startPosition is negative. Affected Node:
class org.eclipse.jdt.core.dom.SimpleName: com
!STACK 0
java.lang.IllegalArgumentException: startPos = -1 and length is 3.
This breaks the rule that length must be 0 if startPosition is negative. Affected Node:
class org.eclipse.jdt.core.dom.SimpleName: com
	at lombok.eclipse.agent.PatchDiagnostics.setSourceRangeCheck(PatchDiagnostics.java:43)
	at org.eclipse.jdt.core.dom.ASTNode.setSourceRange(ASTNode.java)
	at org.eclipse.jdt.core.dom.JavacConverter.convertToType(JavacConverter.java:2880)
	at org.eclipse.jdt.core.dom.JavacConverter.convertToType(JavacConverter.java:2898)
	at org.eclipse.jdt.core.dom.JavacConverter.convertToType(JavacConverter.java:2898)
	at org.eclipse.jdt.core.dom.JavacConverter.convertToType(JavacConverter.java:2898)
	at org.eclipse.jdt.core.dom.JavacConverter.convertToType(JavacConverter.java:2898)
	at org.eclipse.jdt.core.dom.JavacConverter.convertStatement(JavacConverter.java:2373)
	at org.eclipse.jdt.core.dom.JavacConverter.convertBlock(JavacConverter.java:2716)
	at org.eclipse.jdt.core.dom.JavacConverter.convertMethodDecl(JavacConverter.java:995)
	at org.eclipse.jdt.core.dom.JavacConverter.convertBodyDeclaration(JavacConverter.java:773)
	at org.eclipse.jdt.core.dom.JavacConverter.convertClassDecl(JavacConverter.java:625)
	at org.eclipse.jdt.core.dom.JavacConverter.convertClassDecl(JavacConverter.java:545)
	at org.eclipse.jdt.core.dom.JavacConverter.convertBodyDeclaration(JavacConverter.java:776)
	at org.eclipse.jdt.core.dom.JavacConverter.lambda$populateCompilationUnit$2(JavacConverter.java:196)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:215)
	at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1939)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:570)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:560)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:265)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:636)
	at org.eclipse.jdt.core.dom.JavacConverter.populateCompilationUnit(JavacConverter.java:198)
	at org.eclipse.jdt.core.dom.JavacCompilationUnitResolver.parse(JavacCompilationUnitResolver.java:722)
	at org.eclipse.jdt.core.dom.JavacCompilationUnitResolver.toCompilationUnit(JavacCompilationUnitResolver.java:537)
	at org.eclipse.jdt.core.dom.ASTParser.internalCreateASTCached(ASTParser.java:1299)
	at org.eclipse.jdt.core.dom.ASTParser.lambda$1(ASTParser.java:1178)
	at org.eclipse.jdt.internal.core.JavaModelManager.cacheZipFiles(JavaModelManager.java:5692)
	at org.eclipse.jdt.core.dom.ASTParser.internalCreateAST(ASTParser.java:1178)
	at org.eclipse.jdt.core.dom.ASTParser.createAST(ASTParser.java:918)
	at org.eclipse.jdt.internal.core.CompilationUnit.buildStructure(CompilationUnit.java:184)
	at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:246)
	at org.eclipse.jdt.internal.core.JavaElement.openWhenClosed(JavaElement.java:569)
	at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:292)
	at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:278)
	at org.eclipse.jdt.internal.core.Openable.getBuffer(Openable.java:276)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.findElementsAtSelection(JDTUtils.java:1059)
	at org.eclipse.jdt.ls.core.internal.JDTUtils.findElementAtSelection(JDTUtils.java:1045)
	at org.eclipse.jdt.ls.core.internal.handlers.NavigateToDefinitionHandler.computeDefinitionNavigation(NavigateToDefinitionHandler.java:83)
	at org.eclipse.jdt.ls.core.internal.handlers.NavigateToDefinitionHandler.definition(NavigateToDefinitionHandler.java:73)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$7(JDTLanguageServer.java:681)
	at org.eclipse.jdt.ls.core.internal.BaseJDTLanguageServer.lambda$0(BaseJDTLanguageServer.java:87)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:690)
	at java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:527)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:507)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1458)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:2034)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:189)

Is this feature available to try or do we need to wait for some future vscode-java releases with right eclipse JDT core?

[snjeza]

@viswatejan Could you attach a project example reproducing the error?

[viswatejan]

@snjeza , I could not reproduce the same issue with a sample project but I see some other issues related to the autocompletion with the eclipse lombok agent.

Delomboking and removing the Lombok dependency in my project loaded the project fine in the Java Project Explorer.