What??

All primitives in java have a corresponding wrapper classes, e.g. int and Integer
Wrapper classes are reference types

Auto Boxing/Unboxing

Integer i = 5; // auto boxing
int j = i; // auto unboxing
 
// the compiler converts these to:
Integer i = Integer.valueOf(5);
int j = i.intValue();

For what

So that we can make the primitives more general, e.g.

boolean find(Object[] items, Object target) {
	for (Object item : items) {
		if (item.equals(target)) {
			return true;
		}
	}
	return false;
}
 
// this works
Integer[] a = {1,2,3};
find(a, 2); // note that 2 is auto-boxed here
 
// this does not work, since int is not a subtype of Object
int[] a = {1,2,3};
find(a, 2);