Classes as an Object Factory

Write one difference between primitive data types and composite data types.

What are the default values of the primitive data type int and float?

List the variables from those given below that are composite data types: 
(i) static int x;
(ii) arr[i]=10;
(iii) obj.display();
(iv) boolean b;
(v) private char chr;
(vi) String str; 

When a primitive data type is converted to the corresponding object of its class, it is called as ______