https://www.graalvm.org/ 
public abstract class com.oracle.truffle.api.instrumentation.TruffleInstrument
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: com.oracle.truffle.api.instrumentation.TruffleInstrument
  super_class: java.lang.Object
{
  java.util.List<com.oracle.truffle.api.ContextThreadLocal<?>> contextThreadLocals;
    descriptor: Ljava/util/List;
    flags: (0x0000) 
    Signature: Ljava/util/List<Lcom/oracle/truffle/api/ContextThreadLocal<*>;>;

  java.util.List<com.oracle.truffle.api.ContextLocal<?>> contextLocals;
    descriptor: Ljava/util/List;
    flags: (0x0000) 
    Signature: Ljava/util/List<Lcom/oracle/truffle/api/ContextLocal<*>;>;

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=3, locals=1, args_size=0
         0: .line 1413
            ldc Lcom/oracle/truffle/api/instrumentation/InstrumentationHandler;
            invokevirtual java.lang.Class.getName:()Ljava/lang/String;
            iconst_1
            ldc Lcom/oracle/truffle/api/instrumentation/InstrumentationHandler;
            invokevirtual java.lang.Class.getClassLoader:()Ljava/lang/ClassLoader;
            invokestatic java.lang.Class.forName:(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;
            pop
         1: .line 1414
            goto 4
      StackMap locals:
      StackMap stack: java.lang.ClassNotFoundException
         2: astore 0 /* ex */
        start local 0 // java.lang.ClassNotFoundException ex
         3: .line 1415
            new java.lang.IllegalStateException
            dup
            aload 0 /* ex */
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/Throwable;)V
            athrow
        end local 0 // java.lang.ClassNotFoundException ex
         4: .line 1417
      StackMap locals:
      StackMap stack:
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            3    4     0    ex  Ljava/lang/ClassNotFoundException;
      Exception table:
        from    to  target  type
           0     1       2  Class java.lang.ClassNotFoundException

  protected void <init>();
    descriptor: ()V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
         0: .line 127
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 128
            return
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;

  protected abstract void onCreate(com.oracle.truffle.api.instrumentation.TruffleInstrument$Env);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;)V
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      env   

  protected void onFinalize(com.oracle.truffle.api.instrumentation.TruffleInstrument$Env);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=0, locals=2, args_size=2
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
        start local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$Env env
         0: .line 173
            return
        end local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$Env env
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;
            0    1     1   env  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;
    MethodParameters:
      Name  Flags
      env   

  protected void onDispose(com.oracle.truffle.api.instrumentation.TruffleInstrument$Env);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=0, locals=2, args_size=2
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
        start local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$Env env
         0: .line 186
            return
        end local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$Env env
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;
            0    1     1   env  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;
    MethodParameters:
      Name  Flags
      env   

  protected org.graalvm.options.OptionDescriptors getOptionDescriptors();
    descriptor: ()Lorg/graalvm/options/OptionDescriptors;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
         0: .line 208
            getstatic org.graalvm.options.OptionDescriptors.EMPTY:Lorg/graalvm/options/OptionDescriptors;
            areturn
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;

  protected org.graalvm.options.OptionDescriptors getContextOptionDescriptors();
    descriptor: ()Lorg/graalvm/options/OptionDescriptors;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
         0: .line 245
            getstatic org.graalvm.options.OptionDescriptors.EMPTY:Lorg/graalvm/options/OptionDescriptors;
            areturn
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;

  protected final <T> com.oracle.truffle.api.ContextLocal<T> createContextLocal(com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextLocalFactory<T>);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$ContextLocalFactory;)Lcom/oracle/truffle/api/ContextLocal;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
        start local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextLocalFactory factory
         0: .line 308
            getstatic com.oracle.truffle.api.instrumentation.InstrumentAccessor.ENGINE:Lcom/oracle/truffle/api/impl/Accessor$EngineSupport;
            aload 1 /* factory */
            invokevirtual com.oracle.truffle.api.impl.Accessor$EngineSupport.createInstrumentContextLocal:(Ljava/lang/Object;)Lcom/oracle/truffle/api/ContextLocal;
            astore 2 /* local */
        start local 2 // com.oracle.truffle.api.ContextLocal local
         1: .line 309
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.TruffleInstrument.contextLocals:Ljava/util/List;
            ifnonnull 3
         2: .line 310
            aload 0 /* this */
            new java.util.ArrayList
            dup
            invokespecial java.util.ArrayList.<init>:()V
            putfield com.oracle.truffle.api.instrumentation.TruffleInstrument.contextLocals:Ljava/util/List;
         3: .line 313
      StackMap locals: com.oracle.truffle.api.ContextLocal
      StackMap stack:
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.TruffleInstrument.contextLocals:Ljava/util/List;
            aload 2 /* local */
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
         4: .line 314
            goto 7
      StackMap locals:
      StackMap stack: java.lang.UnsupportedOperationException
         5: pop
         6: .line 315
            new java.lang.IllegalStateException
            dup
            ldc "The set of context locals is frozen. Context locals can only be created during construction of the TruffleInstrument subclass."
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
         7: .line 317
      StackMap locals:
      StackMap stack:
            aload 2 /* local */
            areturn
        end local 2 // com.oracle.truffle.api.ContextLocal local
        end local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextLocalFactory factory
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    8     0     this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;
            0    8     1  factory  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$ContextLocalFactory<TT;>;
            1    8     2    local  Lcom/oracle/truffle/api/ContextLocal<TT;>;
      Exception table:
        from    to  target  type
           3     4       5  Class java.lang.UnsupportedOperationException
    Signature: <T:Ljava/lang/Object;>(Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$ContextLocalFactory<TT;>;)Lcom/oracle/truffle/api/ContextLocal<TT;>;
    MethodParameters:
         Name  Flags
      factory  

  protected final <T> com.oracle.truffle.api.ContextThreadLocal<T> createContextThreadLocal(com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextThreadLocalFactory<T>);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$ContextThreadLocalFactory;)Lcom/oracle/truffle/api/ContextThreadLocal;
    flags: (0x0014) ACC_PROTECTED, ACC_FINAL
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
        start local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextThreadLocalFactory factory
         0: .line 385
            getstatic com.oracle.truffle.api.instrumentation.InstrumentAccessor.ENGINE:Lcom/oracle/truffle/api/impl/Accessor$EngineSupport;
            aload 1 /* factory */
            invokevirtual com.oracle.truffle.api.impl.Accessor$EngineSupport.createInstrumentContextThreadLocal:(Ljava/lang/Object;)Lcom/oracle/truffle/api/ContextThreadLocal;
            astore 2 /* local */
        start local 2 // com.oracle.truffle.api.ContextThreadLocal local
         1: .line 386
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.TruffleInstrument.contextThreadLocals:Ljava/util/List;
            ifnonnull 3
         2: .line 387
            aload 0 /* this */
            new java.util.ArrayList
            dup
            invokespecial java.util.ArrayList.<init>:()V
            putfield com.oracle.truffle.api.instrumentation.TruffleInstrument.contextThreadLocals:Ljava/util/List;
         3: .line 390
      StackMap locals: com.oracle.truffle.api.ContextThreadLocal
      StackMap stack:
            aload 0 /* this */
            getfield com.oracle.truffle.api.instrumentation.TruffleInstrument.contextThreadLocals:Ljava/util/List;
            aload 2 /* local */
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
         4: .line 391
            goto 7
      StackMap locals:
      StackMap stack: java.lang.UnsupportedOperationException
         5: pop
         6: .line 392
            new java.lang.IllegalStateException
            dup
            ldc "The set of context thread locals is frozen. Context thread locals can only be created during construction of the TruffleInstrument subclass."
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
         7: .line 394
      StackMap locals:
      StackMap stack:
            aload 2 /* local */
            areturn
        end local 2 // com.oracle.truffle.api.ContextThreadLocal local
        end local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextThreadLocalFactory factory
        end local 0 // com.oracle.truffle.api.instrumentation.TruffleInstrument this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    8     0     this  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument;
            0    8     1  factory  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$ContextThreadLocalFactory<TT;>;
            1    8     2    local  Lcom/oracle/truffle/api/ContextThreadLocal<TT;>;
      Exception table:
        from    to  target  type
           3     4       5  Class java.lang.UnsupportedOperationException
    Signature: <T:Ljava/lang/Object;>(Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$ContextThreadLocalFactory<TT;>;)Lcom/oracle/truffle/api/ContextThreadLocal<TT;>;
    MethodParameters:
         Name  Flags
      factory  
}
SourceFile: "TruffleInstrument.java"
NestMembers:
  com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextLocalFactory  com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextThreadLocalFactory  com.oracle.truffle.api.instrumentation.TruffleInstrument$Env  com.oracle.truffle.api.instrumentation.TruffleInstrument$Env$GuardedExecutableNode  com.oracle.truffle.api.instrumentation.TruffleInstrument$Env$MessageTransportProxy  com.oracle.truffle.api.instrumentation.TruffleInstrument$Env$MessageTransportProxy$MessageEndpointProxy  com.oracle.truffle.api.instrumentation.TruffleInstrument$Provider  com.oracle.truffle.api.instrumentation.TruffleInstrument$Registration
InnerClasses:
  public abstract EngineSupport = com.oracle.truffle.api.impl.Accessor$EngineSupport of com.oracle.truffle.api.impl.Accessor
  protected abstract ContextLocalFactory = com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextLocalFactory of com.oracle.truffle.api.instrumentation.TruffleInstrument
  protected abstract ContextThreadLocalFactory = com.oracle.truffle.api.instrumentation.TruffleInstrument$ContextThreadLocalFactory of com.oracle.truffle.api.instrumentation.TruffleInstrument
  public final Env = com.oracle.truffle.api.instrumentation.TruffleInstrument$Env of com.oracle.truffle.api.instrumentation.TruffleInstrument
  public abstract Provider = com.oracle.truffle.api.instrumentation.TruffleInstrument$Provider of com.oracle.truffle.api.instrumentation.TruffleInstrument
  public abstract Registration = com.oracle.truffle.api.instrumentation.TruffleInstrument$Registration of com.oracle.truffle.api.instrumentation.TruffleInstrument