https://github.com/javaee/jpa-spec: Java(TM) Persistence API 
public interface javax.persistence.MapKey extends java.lang.annotation.Annotation
  minor version: 0
  major version: 59
  flags: flags: (0x2601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT, ACC_ANNOTATION
  this_class: javax.persistence.MapKey
  super_class: java.lang.Object
{
  public abstract java.lang.String name();
    descriptor: ()Ljava/lang/String;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    AnnotationDefault: ""
}
SourceFile: "MapKey.java"
    RuntimeVisibleAnnotations: 
      java.lang.annotation.Target(value = {java.lang.annotation.ElementType.METHOD:Ljava/lang/annotation/ElementType;, java.lang.annotation.ElementType.FIELD:Ljava/lang/annotation/ElementType;})
      java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.RUNTIME:Ljava/lang/annotation/RetentionPolicy;)