https://www.graalvm.org/ 
class com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1 extends java.lang.Thread
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1
  super_class: java.lang.Thread
{
  final com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest this$0;
    descriptor: Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  private final org.graalvm.polyglot.Engine val$engine;
    descriptor: Lorg/graalvm/polyglot/Engine;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  private final org.graalvm.polyglot.Source val$source;
    descriptor: Lorg/graalvm/polyglot/Source;
    flags: (0x1012) ACC_PRIVATE, ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest, org.graalvm.polyglot.Engine, org.graalvm.polyglot.Source);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest;Lorg/graalvm/polyglot/Engine;Lorg/graalvm/polyglot/Source;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=4, args_size=4
        start local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1 this
         0: .line 163
            aload 0 /* this */
            aload 1
            putfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1.this$0:Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest;
            aload 0 /* this */
            aload 2
            putfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1.val$engine:Lorg/graalvm/polyglot/Engine;
            aload 0 /* this */
            aload 3
            putfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1.val$source:Lorg/graalvm/polyglot/Source;
            aload 0 /* this */
            invokespecial java.lang.Thread.<init>:()V
            return
        end local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest$1;
    MethodParameters:
            Name  Flags
      this$0      final
      val$engine  final
      val$source  final

  public void run();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=4, args_size=1
        start local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1 this
         0: .line 166
            aconst_null
            astore 1
            aconst_null
            astore 2
         1: iconst_0
            anewarray java.lang.String
            invokestatic org.graalvm.polyglot.Context.newBuilder:([Ljava/lang/String;)Lorg/graalvm/polyglot/Context$Builder;
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1.val$engine:Lorg/graalvm/polyglot/Engine;
            invokevirtual org.graalvm.polyglot.Context$Builder.engine:(Lorg/graalvm/polyglot/Engine;)Lorg/graalvm/polyglot/Context$Builder;
            invokevirtual org.graalvm.polyglot.Context$Builder.build:()Lorg/graalvm/polyglot/Context;
            astore 3 /* context */
        start local 3 // org.graalvm.polyglot.Context context
         2: .line 167
            aload 3 /* context */
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1.val$source:Lorg/graalvm/polyglot/Source;
            invokevirtual org.graalvm.polyglot.Context.eval:(Lorg/graalvm/polyglot/Source;)Lorg/graalvm/polyglot/Value;
            pop
         3: .line 168
            aload 3 /* context */
            ifnull 9
            aload 3 /* context */
            invokevirtual org.graalvm.polyglot.Context.close:()V
            goto 9
      StackMap locals: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1 java.lang.Throwable java.lang.Throwable org.graalvm.polyglot.Context
      StackMap stack: java.lang.Throwable
         4: astore 1
            aload 3 /* context */
            ifnull 5
            aload 3 /* context */
            invokevirtual org.graalvm.polyglot.Context.close:()V
        end local 3 // org.graalvm.polyglot.Context context
      StackMap locals:
      StackMap stack:
         5: aload 1
            athrow
      StackMap locals:
      StackMap stack: java.lang.Throwable
         6: astore 2
            aload 1
            ifnonnull 7
            aload 2
            astore 1
            goto 8
      StackMap locals:
      StackMap stack:
         7: aload 1
            aload 2
            if_acmpeq 8
            aload 1
            aload 2
            invokevirtual java.lang.Throwable.addSuppressed:(Ljava/lang/Throwable;)V
      StackMap locals:
      StackMap stack:
         8: aload 1
            athrow
         9: .line 169
      StackMap locals:
      StackMap stack:
            return
        end local 0 // com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1 this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0   10     0     this  Lcom/oracle/truffle/api/instrumentation/test/ThreadsEventsTest$1;
            2    5     3  context  Lorg/graalvm/polyglot/Context;
      Exception table:
        from    to  target  type
           2     3       4  any
           1     6       6  any
}
SourceFile: "ThreadsEventsTest.java"
EnclosingMethod: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest.testContextThreads:()V
NestHost: com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest
InnerClasses:
  com.oracle.truffle.api.instrumentation.test.ThreadsEventsTest$1
  public final Builder = org.graalvm.polyglot.Context$Builder of org.graalvm.polyglot.Context