Fixed getDefinedPackage lookup for OpenJ9 (8)

[JonasKunz]

The InstrumentationModuleClassLoaderTest exposed a bug with the current implementation on OpenJ9 (Java 8):

2023-08-22T06:01:32.4244988Z     java.lang.ExceptionInInitializerError
2023-08-22T06:01:32.4245586Z         at java.lang.J9VMInternals.ensureError(J9VMInternals.java:158)
2023-08-22T06:01:32.4246371Z         at java.lang.J9VMInternals.recordInitializationFailure(J9VMInternals.java:147)
2023-08-22T06:01:32.4247576Z         at io.opentelemetry.javaagent.tooling.instrumentation.indy.InstrumentationModuleClassLoaderTest.checkClassLookupPrecedence(InstrumentationModuleClassLoaderTest.java:122)
2023-08-22T06:01:32.4248388Z 
2023-08-22T06:01:32.4249077Z         Caused by:
2023-08-22T06:01:32.4249942Z         java.lang.IllegalStateException: Method should be accessible from here
2023-08-22T06:01:32.4250867Z             at io.opentelemetry.javaagent.tooling.instrumentation.indy.InstrumentationModuleClassLoader.getFindPackageMethod(InstrumentationModuleClassLoader.java:252)
2023-08-22T06:01:32.4262113Z             at io.opentelemetry.javaagent.tooling.instrumentation.indy.InstrumentationModuleClassLoader.<clinit>(InstrumentationModuleClassLoader.java:50)
2023-08-22T06:01:32.4262964Z             ... 1 more
2023-08-22T06:01:32.4263150Z 
2023-08-22T06:01:32.4263276Z             Caused by:
2023-08-22T06:01:32.4264426Z             java.lang.IllegalAccessException: 'io.opentelemetry.javaagent.tooling.instrumentation.indy.InstrumentationModuleClassLoader' no access to: 'java.lang.ClassLoadergetDefinedPackage:(ClassLoader,String)Package/invokeSpecial'
2023-08-22T06:01:32.4265349Z                 at java.lang.invoke.MethodHandles$Lookup.checkAccess(MethodHandles.java:440)
2023-08-22T06:01:32.4265928Z                 at java.lang.invoke.MethodHandles$Lookup.checkAccess(MethodHandles.java:346)
2023-08-22T06:01:32.4266488Z                 at java.lang.invoke.MethodHandles$Lookup.findVirtual(MethodHandles.java:632)
2023-08-22T06:01:32.4267501Z                 at io.opentelemetry.javaagent.tooling.instrumentation.indy.InstrumentationModuleClassLoader.getFindPackageMethod(InstrumentationModuleClassLoader.java:242)
2023-08-22T06:01:32.4268196Z                 ... 2 more

It looks like in OpenJ9 Java 8 there is a getDefinedPackage method, which is however not accessible (it is either private or package private). I've adapted the logic to fallback to getPackage for this case aswell.

[laurit]

closing and reopening