Java - Overloading and Overriding -

01    class subclass extends superclass {} 02    class appsuperclass { 03        /** 04         * @param superclass 05         */ 06        public void print(superclass superclass) { 07            system.out.println("appsuperclass:superclass parameter"); 08      09        } 10        /** 11         * @param subclass 12         */ 13        public void print(subclass subclass) { 14            system.out.println("appsuperclass:subclass parameter"); 15    16        } 17    } 18    19    class appsubclass extends appsuperclass { 20      /** 21       * @param superclass 22       */ 23      public void print(superclass superclass) { 24          system.out.println("appsubclass:superclass parameter"); 25    26      } 27      /** 28       * @param subclass 29       */ 30      public void print(subclass subclass) { 31          system.out.println("appsubclass:subclass parameter"); 32    33      } 34  } 35  public class overloadedtest { 36      public static void main(string[] args) { 37          appsuperclass appsuperclass = new appsuperclass(); 38          appsuperclass appsubclass = new appsubclass(); 39          superclass superclass = new superclass(); 40          superclass subclassinstance = new subclass(); 41          /* 42           * making request print appsuperclass 43           *  1. passing superclass instance 44           *  2. passing subclass instance (*make note of type) <img src="http://s0.wp.com/wp-includes/images/smilies/icon_smile.gif?m=1304052800g" alt=":)" class="wp-smiley"> 45           */ 46    47          appsuperclass.print(superclass); 48          appsuperclass.print(subclassinstance); 49          /* 50           * above repeated appsubclass instance 51           */ 52          appsubclass.print(superclass); 53          appsubclass.print(subclassinstance); 54      } 55    56  } 

when run

       appsuperclass:superclass parameter        appsuperclass:superclass parameter        appsubclass:superclass parameter        appsubclass:superclass parameter 

how can

           appsuperclass:superclass parameter            appsuperclass:subclass parameter            appsubclass:superclass parameter            appsubclass:subclass parameter 

as o/p without changing type of of objects?

your question isn't clear, sounds you're after execution-time overloading, doesn't exist in java. overloads entirely resolved @ compile-time. 1 option this:

public void print(superclass superclass) {     if (superclass instanceof subclass) {]         print((subclass) superclass);         return;     }     system.out.println("appsuperclass:superclass parameter"); } 

note you'd need in override well, or have template method this, , separate printimpl(superclass) method can overridden in subclass.

to take logical extreme, might have:

class appsuperclass {      public final void print(superclass superclass) {         if (superclass subclass) {             printimpl((subclass) superclass);         } else {             printimpl(superclass);                     }     }      protected void printimpl(superclass superclass) {         ...     }      protected void printimpl(subclass subclass) {        ...     } } 

appsubclass override printimpl (one or both overloads).

edit: noted in comments, alternative use visitor pattern. it's not pattern i'm terribly fond of, if can modify superclass , subclass know appsuperclass (or interface implements) work you.