https://openjdk.java.net/ 
public interface sun.awt.WindowClosingSupport
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: sun.awt.WindowClosingSupport
  super_class: java.lang.Object
{
  public abstract sun.awt.WindowClosingListener getWindowClosingListener();
    descriptor: ()Lsun/awt/WindowClosingListener;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT

  public abstract void setWindowClosingListener(sun.awt.WindowClosingListener);
    descriptor: (Lsun/awt/WindowClosingListener;)V
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      wcl   
}
SourceFile: "WindowClosingSupport.java"