https://www.graalvm.org/ 
class com.oracle.truffle.sl.test.SLInteropObjectTest$TestType implements org.graalvm.polyglot.proxy.ProxyInstantiable
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.sl.test.SLInteropObjectTest$TestType
  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.sl.test.SLInteropObjectTest$TestType this
         0: .line 103
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.truffle.sl.test.SLInteropObjectTest$TestType this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/sl/test/SLInteropObjectTest$TestType;

  public java.lang.Object newInstance(org.graalvm.polyglot.Value[]);
    descriptor: ([Lorg/graalvm/polyglot/Value;)Ljava/lang/Object;
    flags: (0x0081) ACC_PUBLIC, ACC_VARARGS
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.sl.test.SLInteropObjectTest$TestType this
        start local 1 // org.graalvm.polyglot.Value[] arguments
         0: .line 107
            new com.oracle.truffle.sl.test.SLInteropObjectTest$TestObject
            dup
            invokespecial com.oracle.truffle.sl.test.SLInteropObjectTest$TestObject.<init>:()V
            areturn
        end local 1 // org.graalvm.polyglot.Value[] arguments
        end local 0 // com.oracle.truffle.sl.test.SLInteropObjectTest$TestType this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    1     0       this  Lcom/oracle/truffle/sl/test/SLInteropObjectTest$TestType;
            0    1     1  arguments  [Lorg/graalvm/polyglot/Value;
    MethodParameters:
           Name  Flags
      arguments  
}
SourceFile: "SLInteropObjectTest.java"
NestHost: com.oracle.truffle.sl.test.SLInteropObjectTest
InnerClasses:
  private TestObject = com.oracle.truffle.sl.test.SLInteropObjectTest$TestObject of com.oracle.truffle.sl.test.SLInteropObjectTest
  private TestType = com.oracle.truffle.sl.test.SLInteropObjectTest$TestType of com.oracle.truffle.sl.test.SLInteropObjectTest