getParameterInfo - NullPointerException

Hi, I tried to get info about parameters in method. But I catch an exception:

System.out.println(Arrays.toString(method.getParameterInfo()));

Exception in thread "Thread-6" java.lang.NullPointerException
	at io.github.classgraph.MethodParameterInfo.getAnnotationInfo(MethodParameterInfo.java:138)
	at io.github.classgraph.MethodParameterInfo.toString(MethodParameterInfo.java:167)

Snippet of scaner:

try (ScanResult scanResult = new ClassGraph()
        .enableAllInfo()
        .enableSystemPackages()
        .disableJarScanning()
        .disableDirScanning()
        .whitelistPackages("java", "java.lang", "javax", "javafx")
        .blacklistPackages("java.applet", "java.awt")
        .scan()) {
// ...
}

[lukehutch]

@MrChebik Glad it’s working for you with the latest version.

See the Javadoc for MethodParameterInfo#getName():

https://github.com/classgraph/classgraph/blob/master/src/main/java/io/github/classgraph/MethodParameterInfo.java#L74

You need to compile your code with the -parameters switch (and you have to be using JDK 8+) for method parameter names to be stored in the classfile by the compiler. If you don’t do that, then the toString() method just uses “_unnamed_param” instead.

(Eclipse has its own equivalent config option to the -parameters switch.)

[lukehutch]

Hi @MrChebik, I believe this is a bug that was fixed a few versions ago. Can you please test with the latest version and see if it resolves the problem?