Just Java™ 2

Autoboxing and Unboxing

Autoboxing is a feature that came into Java with the JDK 1.5 release. It recognizes the very close relationship between primitive variables and objects of their corresponding wrapper type, and provides a little extra help from the compiler. Autoboxing says that you can convert from one to the other without explicitly writing the code. The compiler will provide it for you.

In releases before 1.5, you could get an int value into a java.lang.Integer like this:

int i = 27;Integer myInt = new Integer(i);

With autoboxing, you can make the assignment directly, and the compiler looks at the types of the variables, and says ...