HashMap and int as key

Question

I am trying to build a HashMap which will have integer as keys and objects as values.

My syntax is:

HashMap myMap = new HashMap&         


        

Answer 1

HashMap does not allow primitive data types as arguments. It can only accept objects so

HashMap myMap = new HashMap();

will not work.

You have to change the declaration to

HashMap myMap = new HashMap();

so even when you do the following

myMap.put(2,myObject);

The primitive data type is autoboxed to an Integer object.

8 (int) === boxing ===> 8 (Integer)

You can read more on autoboxing here http://docs.oracle.com/javase/tutorial/java/data/autoboxing.html