https://www.graalvm.org/ 
final class com.oracle.truffle.api.test.polyglot.ValueAPITest$NumberWrapper implements com.oracle.truffle.api.interop.TruffleObject
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: com.oracle.truffle.api.test.polyglot.ValueAPITest$NumberWrapper
  super_class: java.lang.Object
{
  final java.lang.Number number;
    descriptor: Ljava/lang/Number;
    flags: (0x0010) ACC_FINAL

  void <init>(java.lang.Number);
    descriptor: (Ljava/lang/Number;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.api.test.polyglot.ValueAPITest$NumberWrapper this
        start local 1 // java.lang.Number number
         0: .line 1921
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 1922
            aload 0 /* this */
            aload 1 /* number */
            putfield com.oracle.truffle.api.test.polyglot.ValueAPITest$NumberWrapper.number:Ljava/lang/Number;
         2: .line 1923
            return
        end local 1 // java.lang.Number number
        end local 0 // com.oracle.truffle.api.test.polyglot.ValueAPITest$NumberWrapper this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    3     0    this  Lcom/oracle/truffle/api/test/polyglot/ValueAPITest$NumberWrapper;
            0    3     1  number  Ljava/lang/Number;
    MethodParameters:
        Name  Flags
      number  
}
SourceFile: "ValueAPITest.java"
NestHost: com.oracle.truffle.api.test.polyglot.ValueAPITest
InnerClasses:
  final NumberWrapper = com.oracle.truffle.api.test.polyglot.ValueAPITest$NumberWrapper of com.oracle.truffle.api.test.polyglot.ValueAPITest
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportLibrary(value = Lcom/oracle/truffle/api/interop/InteropLibrary;, delegateTo = "number")