Java how does HashMap identify the key object if hashCode are the same and equals is true? -

i thought hat hashmap identifying keys using hascode , equals. code still not give me value back. missing?

import java.util.hashmap; import java.util.map;  /**  * created kic on 25.04.15.  */ public class typepair {     private final class a;     private final class b;      public typepair(class a, class b) {         this.a = a;         this.b = b;     }      public typepair(object a, object b) {         this.a = a.getclass();         this.b = b.getclass();     }      public boolean ispair (object a, object b) {         return this.a.isassignablefrom(a.getclass()) && this.b.isassignablefrom(b.getclass());     }      @override     public boolean equals(object obj) {         if (obj instanceof typepair) {             return a.isassignablefrom(((typepair) obj).a) && b.isassignablefrom(((typepair) obj).b);         } else {             return false;         }     }      @override     public int hashcode() {         return 1;     }      public static void main(string[] args) {         typepair = new typepair(number.class, string.class);         typepair b = new typepair(12, "hello");          map<typepair, boolean> test = new hashmap<>();         test.put(a, true);          system.out.println(a.hashcode() == b.hashcode());         system.out.println(a.equals(b));         system.out.println("und? " + test.get(a));         system.out.println("und? " + test.get(b));     } } 

this code prints:

true true und? true und? null 

your implementation of equals() violating contract (it not symmetric), that's why not work correctly.

you need use like:

@override public boolean equals(object obj) {     if (obj instanceof typepair) {         typepair objtypepair = (typepair) obj;         return            .isassignablefrom(objtypepair.a) && b            .isassignablefrom(objtypepair.b) ||                objtypepair.a.isassignablefrom(a)             && objtypepair.b.isassignablefrom(b);     } else {         return false;     } }