https://www.graalvm.org/ 
class com.oracle.truffle.tools.coverage.CoverageTracker$4 implements com.oracle.truffle.api.instrumentation.LoadSourceSectionListener
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.truffle.tools.coverage.CoverageTracker$4
  super_class: java.lang.Object
{
  final com.oracle.truffle.tools.coverage.CoverageTracker this$0;
    descriptor: Lcom/oracle/truffle/tools/coverage/CoverageTracker;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.oracle.truffle.tools.coverage.CoverageTracker);
    descriptor: (Lcom/oracle/truffle/tools/coverage/CoverageTracker;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.tools.coverage.CoverageTracker$4 this
         0: .line 305
            aload 0 /* this */
            aload 1
            putfield com.oracle.truffle.tools.coverage.CoverageTracker$4.this$0:Lcom/oracle/truffle/tools/coverage/CoverageTracker;
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.truffle.tools.coverage.CoverageTracker$4 this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/tools/coverage/CoverageTracker$4;
    MethodParameters:
        Name  Flags
      this$0  final

  public void onLoad(com.oracle.truffle.api.instrumentation.LoadSourceSectionEvent);
    descriptor: (Lcom/oracle/truffle/api/instrumentation/LoadSourceSectionEvent;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.tools.coverage.CoverageTracker$4 this
        start local 1 // com.oracle.truffle.api.instrumentation.LoadSourceSectionEvent event
         0: .line 308
            aload 0 /* this */
            getfield com.oracle.truffle.tools.coverage.CoverageTracker$4.this$0:Lcom/oracle/truffle/tools/coverage/CoverageTracker;
            aload 1 /* event */
            invokevirtual com.oracle.truffle.tools.coverage.CoverageTracker.addRoot:(Lcom/oracle/truffle/api/instrumentation/LoadSourceSectionEvent;)V
         1: .line 309
            return
        end local 1 // com.oracle.truffle.api.instrumentation.LoadSourceSectionEvent event
        end local 0 // com.oracle.truffle.tools.coverage.CoverageTracker$4 this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0    2     0   this  Lcom/oracle/truffle/tools/coverage/CoverageTracker$4;
            0    2     1  event  Lcom/oracle/truffle/api/instrumentation/LoadSourceSectionEvent;
    MethodParameters:
       Name  Flags
      event  
}
SourceFile: "CoverageTracker.java"
EnclosingMethod: com.oracle.truffle.tools.coverage.CoverageTracker.instrumentLoadedRoots:(Lcom/oracle/truffle/api/instrumentation/Instrumenter;Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter;)V
NestHost: com.oracle.truffle.tools.coverage.CoverageTracker
InnerClasses:
  com.oracle.truffle.tools.coverage.CoverageTracker$4