https://www.graalvm.org/ 
public class com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument extends com.oracle.truffle.api.instrumentation.TruffleInstrument
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument
  super_class: com.oracle.truffle.api.instrumentation.TruffleInstrument
{
  java.lang.String fceCode;
    descriptor: Ljava/lang/String;
    flags: (0x0000) 

  java.lang.Object returnValue;
    descriptor: Ljava/lang/Object;
    flags: (0x0000) 

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument this
         0: .line 775
            aload 0 /* this */
            invokespecial com.oracle.truffle.api.instrumentation.TruffleInstrument.<init>:()V
            return
        end local 0 // com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/sl/test/SLInstrumentLegacyTest$EarlyReturnLegacyInstrument;

  protected void onCreate(com.oracle.truffle.api.instrumentation.TruffleInstrument$Env);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=6, locals=2, args_size=2
        start local 0 // com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument this
        start local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$Env env
         0: .line 782
            aload 1 /* env */
            aload 0 /* this */
            invokevirtual com.oracle.truffle.api.instrumentation.TruffleInstrument$Env.registerService:(Ljava/lang/Object;)V
         1: .line 783
            aload 1 /* env */
            invokevirtual com.oracle.truffle.api.instrumentation.TruffleInstrument$Env.getInstrumenter:()Lcom/oracle/truffle/api/instrumentation/Instrumenter;
            invokestatic com.oracle.truffle.api.instrumentation.SourceSectionFilter.newBuilder:()Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter$Builder;
            iconst_1
            anewarray java.lang.Class
            dup
            iconst_0
            ldc Lcom/oracle/truffle/api/instrumentation/StandardTags$CallTag;
            aastore
            invokevirtual com.oracle.truffle.api.instrumentation.SourceSectionFilter$Builder.tagIs:([Ljava/lang/Class;)Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter$Builder;
            invokevirtual com.oracle.truffle.api.instrumentation.SourceSectionFilter$Builder.build:()Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter;
            new com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument$1
            dup
            aload 0 /* this */
            invokespecial com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument$1.<init>:(Lcom/oracle/truffle/sl/test/SLInstrumentLegacyTest$EarlyReturnLegacyInstrument;)V
            invokevirtual com.oracle.truffle.api.instrumentation.Instrumenter.attachExecutionEventListener:(Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter;Lcom/oracle/truffle/api/instrumentation/ExecutionEventListener;)Lcom/oracle/truffle/api/instrumentation/EventBinding;
            pop
         2: .line 806
            return
        end local 1 // com.oracle.truffle.api.instrumentation.TruffleInstrument$Env env
        end local 0 // com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/oracle/truffle/sl/test/SLInstrumentLegacyTest$EarlyReturnLegacyInstrument;
            0    3     1   env  Lcom/oracle/truffle/api/instrumentation/TruffleInstrument$Env;
    MethodParameters:
      Name  Flags
      env   
}
SourceFile: "SLInstrumentLegacyTest.java"
NestHost: com.oracle.truffle.sl.test.SLInstrumentLegacyTest
InnerClasses:
  public final Builder = com.oracle.truffle.api.instrumentation.SourceSectionFilter$Builder of com.oracle.truffle.api.instrumentation.SourceSectionFilter
  public final CallTag = com.oracle.truffle.api.instrumentation.StandardTags$CallTag of com.oracle.truffle.api.instrumentation.StandardTags
  public final Env = com.oracle.truffle.api.instrumentation.TruffleInstrument$Env of com.oracle.truffle.api.instrumentation.TruffleInstrument
  public abstract Registration = com.oracle.truffle.api.instrumentation.TruffleInstrument$Registration of com.oracle.truffle.api.instrumentation.TruffleInstrument
  public EarlyReturnLegacyInstrument = com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument of com.oracle.truffle.sl.test.SLInstrumentLegacyTest
  com.oracle.truffle.sl.test.SLInstrumentLegacyTest$EarlyReturnLegacyInstrument$1
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.instrumentation.TruffleInstrument$Registration(id = "testEarlyReturnLegacy", services = {Lcom/oracle/truffle/sl/test/SLInstrumentLegacyTest$EarlyReturnLegacyInstrument;})