https://openjdk.java.net/ 
public interface sun.management.HotspotMemoryMBean
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: sun.management.HotspotMemoryMBean
  super_class: java.lang.Object
{
  public abstract java.util.List<sun.management.counter.Counter> getInternalMemoryCounters();
    descriptor: ()Ljava/util/List;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    Signature: ()Ljava/util/List<Lsun/management/counter/Counter;>;
}
SourceFile: "HotspotMemoryMBean.java"