code: public static boolean setAboutHandler(Object target, Method aboutHandler) {
          boolean enableAboutMenu = (target != null && aboutHandler != null);
          if (enableAboutMenu) {
              setHandler(new OSXAdapter("handleAbout", target, aboutHandler));
          }
          // If we're setting a handler, enable the About menu item by calling
          // com.apple.eawt.Application reflectively
          try {
              Method enableAboutMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledAboutMenu", new Class[] { boolean.class });
              enableAboutMethod.invoke(macOSXApplication, new Object[] { Boolean.valueOf(enableAboutMenu) });
              return true;
          } catch (Exception ex) {
              System.err.println("OSXAdapter could not access the About Menu");
              ex.printStackTrace();
              return false;
          }
      }
docs: They will be called when the About menu item is selected from the application menu