https://www.graalvm.org/ 
class com.oracle.truffle.api.library.test.GR18252Test$BMessages extends com.oracle.truffle.api.library.test.GR18252Test$AMessages
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.api.library.test.GR18252Test$BMessages
  super_class: com.oracle.truffle.api.library.test.GR18252Test$AMessages
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.api.library.test.GR18252Test$BMessages this
         0: .line 118
            aload 0 /* this */
            invokespecial com.oracle.truffle.api.library.test.GR18252Test$AMessages.<init>:()V
            return
        end local 0 // com.oracle.truffle.api.library.test.GR18252Test$BMessages this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/api/library/test/GR18252Test$BMessages;

  public static java.lang.Object get(com.oracle.truffle.api.library.test.GR18252Test$Data);
    descriptor: (Lcom/oracle/truffle/api/library/test/GR18252Test$Data;)Ljava/lang/Object;
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.api.library.test.GR18252Test$Data receiver
         0: .line 132
            aload 0 /* receiver */
            getfield com.oracle.truffle.api.library.test.GR18252Test$Data.value:Ljava/lang/Object;
            areturn
        end local 0 // com.oracle.truffle.api.library.test.GR18252Test$Data receiver
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    1     0  receiver  Lcom/oracle/truffle/api/library/test/GR18252Test$Data;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportMessage()
    MethodParameters:
          Name  Flags
      receiver  
}
SourceFile: "GR18252Test.java"
NestHost: com.oracle.truffle.api.library.test.GR18252Test
InnerClasses:
  AMessages = com.oracle.truffle.api.library.test.GR18252Test$AMessages of com.oracle.truffle.api.library.test.GR18252Test
  BMessages = com.oracle.truffle.api.library.test.GR18252Test$BMessages of com.oracle.truffle.api.library.test.GR18252Test
  public Is = com.oracle.truffle.api.library.test.GR18252Test$BMessages$Is of com.oracle.truffle.api.library.test.GR18252Test$BMessages
  Data = com.oracle.truffle.api.library.test.GR18252Test$Data of com.oracle.truffle.api.library.test.GR18252Test
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.library.ExportLibrary(value = Lcom/oracle/truffle/api/library/test/GR18252Test$ALibrary;, receiverType = Lcom/oracle/truffle/api/library/test/GR18252Test$Data;)