https://www.graalvm.org/ 
class com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent
  super_class: java.lang.Object
{
  final boolean isNew;
    descriptor: Z
    flags: (0x0010) ACC_FINAL

  final java.lang.Thread thread;
    descriptor: Ljava/lang/Thread;
    flags: (0x0010) ACC_FINAL

  final com.oracle.truffle.api.TruffleContext context;
    descriptor: Lcom/oracle/truffle/api/TruffleContext;
    flags: (0x0010) ACC_FINAL

  void <init>(boolean, java.lang.Thread, com.oracle.truffle.api.TruffleContext);
    descriptor: (ZLjava/lang/Thread;Lcom/oracle/truffle/api/TruffleContext;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=4, args_size=4
        start local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent this
        start local 1 // boolean isNew
        start local 2 // java.lang.Thread thread
        start local 3 // com.oracle.truffle.api.TruffleContext context
         0: .line 318
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 319
            aload 0 /* this */
            iload 1 /* isNew */
            putfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent.isNew:Z
         2: .line 320
            aload 0 /* this */
            aload 2 /* thread */
            putfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent.thread:Ljava/lang/Thread;
         3: .line 321
            aload 0 /* this */
            aload 3 /* context */
            putfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent.context:Lcom/oracle/truffle/api/TruffleContext;
         4: .line 322
            return
        end local 3 // com.oracle.truffle.api.TruffleContext context
        end local 2 // java.lang.Thread thread
        end local 1 // boolean isNew
        end local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    5     0     this  Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest$ThreadEvent;
            0    5     1    isNew  Z
            0    5     2   thread  Ljava/lang/Thread;
            0    5     3  context  Lcom/oracle/truffle/api/TruffleContext;
    MethodParameters:
         Name  Flags
      isNew    
      thread   
      context  

  public java.lang.String toString();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent this
         0: .line 326
            new java.lang.StringBuilder
            dup
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent.isNew:Z
            ifeq 1
            ldc "New "
            goto 2
      StackMap locals: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent
      StackMap stack: new 0 new 0
         1: ldc "Passed "
      StackMap locals: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent
      StackMap stack: new 0 new 0 java.lang.String
         2: invokestatic java.lang.String.valueOf:(Ljava/lang/Object;)Ljava/lang/String;
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent.thread:Ljava/lang/Thread;
            invokevirtual java.lang.Thread.toString:()Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            ldc " context = "
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent.context:Lcom/oracle/truffle/api/TruffleContext;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/Object;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            areturn
        end local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest$ThreadEvent;
}
SourceFile: "ThreadsEventsTest.java"
NestHost: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest
InnerClasses:
  private ThreadEvent = com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$ThreadEvent of com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest