[GR-53978] Class graph unable to load classes with GraalVM JDK21

[anshu-zs]

Hi I am trying to initialize ClassScanner at build time, but it's not able to load classes

Here is my classScanner:

public class ClassScanner {
    private static ScanResult scanResult;

    static {
        scanResult = new ClassGraph().disableModuleScanning() // added for GraalVM
                 .disableDirScanning() // added for GraalVM
                 .disableNestedJarScanning() // added for GraalVM
                 .disableRuntimeInvisibleAnnotations() // added for GraalVM
                .addClassLoader(ClassLoader.getSystemClassLoader()) // see
                .enableAnnotationInfo().enableMethodInfo().initializeLoadedClasses().scan();
    }
    
        public Set<Class> findAllClassesImplementingInterfaces(Class interfaceName) {
        Set<Class> classSet = new HashSet<>();
        ClassInfoList classInfos = scanResult.getClassesImplementing(interfaceName);
        for (ClassInfo clazz : classInfos) {
            classSet.add(clazz.loadClass());
        }
        System.out.println("ScanResult:   "+classSet);
        return classSet;
    }

ClassScanner usage

ClassScanner classScanner =new ClassScanner();
classScanner.findAllClassesImplementingInterfaces(IContext.class)

Here are the logs when I run the native image:

INFO [17:48:16]  Default properties successfully read. 
      (Memory: 2621440 Threads: 2)
INFO [17:48:16]  Loaded config from file: .env 
      (Memory: 3145728 Threads: 2)
INFO [17:48:16]  System environment properties successfully read. 
      (Memory: 3145728 Threads: 2)
      
scanResult: []

INFO [17:48:16]  Initializing dependencies. 
      (Memory: 3145728 Threads: 2)
INFO [17:48:16]  Dependencies successfully created. 
      (Memory: 3145728 Threads: 2)
INFO [17:48:16]  Started Application in 5.042 seconds 
      (Memory: 3145728 Threads: 2)
INFO [17:48:16]  Stopping application 
      (Memory: 4718592 Threads: 4)
INFO [17:48:16]  Application stopped 
      (Memory: 4718592 Threads: 4)

Here as u can see my scanResult shows empty array

---

When I run my application locally instead of running native image I get scanResult as

scanResult: [class com.zopsmart.rocket.context.AppContext, class com.zopsmart.rocket.context.ServerContext]

GraalVM version
GraalVM JDK 21

[selhagani]

Hi @anshu-zs,

Thanks for reaching out to us!

I wanted to let you know that there's a compatibility issue between ClassGraph and GraalVM. When compiling to Native Image with GraalVM, the JARs on the classpath are no longer available. This means that any metadata associated with resources in those files becomes invalid.

[anshu-zs]

Hi @anshu-zs,

Thanks for reaching out to us!

I wanted to let you know that there's a compatibility issue between ClassGraph and GraalVM. When compiling to Native Image with GraalVM, the JARs on the classpath are no longer available. This means that any metadata associated with resources in those files becomes invalid.

Hi @selhagani Thank you for replying, So is there any workaround for this?

[selhagani]

Hi @anshu-zs, I understand your concern. Currently, there aren't any workarounds available for this situation. However, I'll take this opportunity to forward your feedback as a feature request to our team. Thank you for bringing this to our attention!