java 1.5 generic and autocasting

[Steve Jiang]

From http://java.sun.com/j2se/1.5.0/docs/guide/collections/changes5.html,

Generics - adds compile-time type safety to the collections framework and eliminates the need to cast when reading elements from collections.
Enhanced for loop - eliminates the need for explicit iterators when interating over collections.
Autoboxing/unboxing - automatically converts primitives (such as int) to wrapper classes (such as Integer) when inserting them into collections, and converts wrapper class instances to primitives when reading from collections.



I think the following code should work, but the compiler complains " Incompatbable type for Object and int or Integer" , what is wrong with me for generic and autocasting?

Thanks,

    
      HashMap count = new HashMap<String, Integer>();
       int i=0;
       String str= "" ;
       count.put(str, i);   //works fine.
    
       i = count.get(str);   //not work
       Integer inte = count.get(str);  // not work
 

[ January 17, 2008: Message edited by: Steve Jiang ]

[Rob Spoor]

You declared the HashMap without generics, so it only knows that it returns Object.

If you change that into HashMap<String, Integer>, or even better Map<String, Integer> it should work.