Autoboxing: So I can write: Integer i = 0; instead of: Integer i = new Integer(0);

Question

Autoboxing seems to come down to the fact that I can write:

Integer i = 0; 

instead of:

Integer i = new Integer(0);


        

Answer 1

Makes for more readable and neater code. Especially if you're doing operations (Since Java doesn't have operator overloading).

Answer 2

BTW

Integer i = 0;

is equivalent to

Integer i = Integer.valueOf(0);

The distinction is that valueOf() does not create a new object for values between -128 and 127 (Apparently this will be tunable if Java 6u14)

Answer 3

It exists so that you can write code like

List<Integer> is = new ArrayList<Integer>();
is.add(1); // auto-boxing
is.add(2);
is.add(3);

int sum = 0;
for (int i : is)  // auto-unboxing
{
    sum += i;
}

For single integers you should by default use the type int, not Integer. Integer is mostly for use in collections.

Beware that a Long is different from the same value as an Integer (using equals()), but as a long it is equal to an int (using ==).