sdk-api-gen causes java build to fail in cursor

[cameronbraid]

I get this error in my java build log, and it breaks compilation of all java files in my project

The build works fine with mvn compile but not with the java extension in cursor

!MESSAGE Errors running builder 'Java Builder' on project '....'.
!STACK 0
java.lang.IllegalArgumentException: Unsupported location: ANNOTATION_PROCESSOR_PATH
	at org.eclipse.jdt.internal.apt.pluggable.core.filer.IdeFilerImpl.getFileFromOutputLocation(IdeFilerImpl.java:234)
	at org.eclipse.jdt.internal.apt.pluggable.core.filer.IdeFilerImpl.getResource(IdeFilerImpl.java:202)
	at dev.restate.sdk.gen.FilerTemplateLoader$1.content(FilerTemplateLoader.java:38)
	at com.github.jknack.handlebars.internal.HbsParserFactory$1.parse(HbsParserFactory.java:77)
	at com.github.jknack.handlebars.cache.NullTemplateCache.get(NullTemplateCache.java:54)
	at com.github.jknack.handlebars.Handlebars.compile(Handlebars.java:575)
	at com.github.jknack.handlebars.Handlebars.compile(Handlebars.java:500)
	at com.github.jknack.handlebars.Handlebars.compile(Handlebars.java:481)
	at dev.restate.sdk.gen.template.HandlebarsTemplateEngine.lambda$new$1(HandlebarsTemplateEngine.java:73)
	at java.base/java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Unknown Source)
	at java.base/java.util.stream.ReduceOps$3ReducingSink.accept(Unknown Source)
	at java.base/java.util.Iterator.forEachRemaining(Unknown Source)
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at dev.restate.sdk.gen.template.HandlebarsTemplateEngine.<init>(HandlebarsTemplateEngine.java:68)
	at dev.restate.sdk.gen.ServiceProcessor.init(ServiceProcessor.java:53)
	at org.eclipse.jdt.internal.apt.pluggable.core.dispatch.IdeAnnotationProcessorManager.discoverNextProcessor(IdeAnnotationProcessorManager.java:91)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.round(RoundDispatcher.java:120)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.BaseAnnotationProcessorManager.processAnnotations(BaseAnnotationProcessorManager.java:177)
	at org.eclipse.jdt.internal.apt.pluggable.core.dispatch.IdeAnnotationProcessorManager.processAnnotations(IdeAnnotationProcessorManager.java:132)
	at org.eclipse.jdt.internal.compiler.Compiler.processAnnotations(Compiler.java:859)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:333)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:309)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:441)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.compile(BatchImageBuilder.java:250)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:400)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.build(BatchImageBuilder.java:118)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.buildAll(JavaBuilder.java:311)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:223)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1109)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:299)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:355)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:449)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:452)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:564)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:512)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:594)
	at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:208)
	at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:309)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

ide

Version: 1.3.9
VSCode Version: 1.99.3
Commit: 54c27320fab08c9f5dd5873f07fca101f7a3e070
Date: 2025-08-01T20:15:21.999Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Linux x64 6.15.9-arch1-1

plugins

Identifier
redhat.java
Version
1.44.0

Identifier
vscjava.vscode-maven
Version
0.44.0

pom extract

      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.14.0</version>
        <configuration combine.self="override">
          <release>17</release>
          <annotationProcessorPaths>
            <path>
              <groupId>org.projectlombok</groupId>
              <artifactId>lombok</artifactId>
              <version>1.18.34</version>
            </path>
            <path>
              <groupId>dev.restate</groupId>
              <artifactId>sdk-api-gen</artifactId>
              <version>2.2.0</version>
            </path>
          </annotationProcessorPaths>
        </configuration>

      </plugin>

[cameronbraid]

❯ java -version
openjdk version "17.0.14" 2025-01-21
OpenJDK Runtime Environment Temurin-17.0.14+7 (build 17.0.14+7)
OpenJDK 64-Bit Server VM Temurin-17.0.14+7 (build 17.0.14+7, mixed mode, sharing)

[slinkydeveloper]

Seems there is some special guide for using annotation processing with maven in vscode, check this out https://github.com/redhat-developer/vscode-java/wiki/Annotation-Processing-support-for-Maven-projects

[cameronbraid]

I don't know if that is related. I have it already working with lombok in vscode/cursor

[slinkydeveloper]

lombok is a bit different from "standard" annotation processors, so i wouldn't assume if it works for lombok, then it works with the sdk annotation processor too. Perhaps give a try and let me know if it works.

[cameronbraid]

I've followed that page, and added the apt-maven-plugin to do the annotation processing instead of the maven compiler.

It results in other build failures :

java.lang.NoClassDefFoundError: com/github/jknack/handlebars/io/TemplateLoader

And if I try and run the build in maven I get

[WARNING] The POM for com.github.jknack:handlebars:jar:4.3.1 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model for com.github.jknack:handlebars:4.3.1
[ERROR] Invalid packaging for parent POM com.github.jknack:handlebars.java:4.3.1, must be "pom" but is "jar" @ com.github.jknack:handlebars.java:4.3.1

Should I try manually adding the transitive dependencies of sdk-api-gen to my project ? Or is this not the path to follow ?

[cameronbraid]

I've also use https://mapstruct.org/ in another project and its annotation processor worked in vscode

[cameronbraid]

I've played around for a while and ended up seeing if I could implement a hack.

diff --git a/sdk-api-gen/src/main/java/dev/restate/sdk/gen/FilerTemplateLoader.java b/sdk-api-gen/src/main/java/dev/restate/sdk/gen/FilerTemplateLoader.java
index ef6707d..dd3658c 100644
--- a/sdk-api-gen/src/main/java/dev/restate/sdk/gen/FilerTemplateLoader.java
+++ b/sdk-api-gen/src/main/java/dev/restate/sdk/gen/FilerTemplateLoader.java
@@ -34,13 +34,24 @@ class FilerTemplateLoader extends AbstractTemplateLoader {
     return new TemplateSource() {
       @Override
       public String content(Charset charset) throws IOException {
-        return filer
-            .getResource(
-                StandardLocation.ANNOTATION_PROCESSOR_PATH,
-                path.getParent().toString().replace('/', '.'),
-                path.getFileName().toString())
-            .getCharContent(true)
-            .toString();
+        try {
+          return filer
+              .getResource(
+                  StandardLocation.ANNOTATION_PROCESSOR_PATH,
+                  path.getParent().toString().replace('/', '.'),
+                  path.getFileName().toString())
+              .getCharContent(true)
+              .toString();
+
+        } catch (java.lang.IllegalArgumentException iae) {
+          // in vscode/cursor this happens https://github.com/restatedev/sdk-java/issues/516
+          // so fallback to using the classloader
+          try (var stream2 = getClass().getResourceAsStream("/" + location)) {
+            return new String(stream2.readAllBytes(), charset);
+          } catch (Exception classLoaderException) {
+            throw iae; // throw the original exception to retain the original behaviour
+          }
+        }

I tried first of all seeing if StandardLocation.CLASS_PATH (and all other enum values) would work, but the same error happens.

So I don't know what the root cause of this is. But the above patch allows me to at least use restate in my legacy java app.

[slinkydeveloper]

I tried first of all seeing if StandardLocation.CLASS_PATH (and all other enum values) would work, but the same error happens.

Not even SOURCE_PATH? the javadocs says that must be supported by Filer implementations...

[slinkydeveloper]

The fix indeed makes sense, thanks for that! I'll merge and release a bugfix release.

[cameronbraid]

I tied all StandardLocation.values() in a loop and they all failed so I guess the Filer was really broken.

Thanks for merging the patch - i've had success using my own patched jar thanks to your gradle build working out of the box.

Looking forward to using restate.. I'm currenlty using temporal for a few things, but I really like the approach that restate takes

Cheers

Cameron

[slinkydeveloper]

Glad that I could help! and let me know if there's something else that we can do!