https://www.graalvm.org/ 
class com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest$TestObject implements com.oracle.truffle.api.interop.TruffleObject
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest$TestObject
  super_class: java.lang.Object
{
  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest$TestObject this
         0: .line 62
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest$TestObject this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/nfi/test/WrappedPrimitiveNFITest$TestObject;
}
SourceFile: "WrappedPrimitiveNFITest.java"
NestHost: com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest
InnerClasses:
  private TestObject = com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest$TestObject of com.oracle.truffle.nfi.test.WrappedPrimitiveNFITest