https://openjdk.java.net/ 
public abstract class jdk.vm.ci.code.ReferenceMap
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: jdk.vm.ci.code.ReferenceMap
  super_class: java.lang.Object
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // jdk.vm.ci.code.ReferenceMap this
         0: .line 30
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // jdk.vm.ci.code.ReferenceMap this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Ljdk/vm/ci/code/ReferenceMap;
}
SourceFile: "ReferenceMap.java"