Boxing and Unboxing

Boxing is name given to the process whereby a value type is converted into a reference type. When you box a variable, you are creating a reference variable that points to a new copy on the heap. You will encounter unboxing when you use classes designed for use with objects: for example, using an ArrayList to store integers. When you store an integer in the ArrayList, it's boxed. When you retrieve an integer, it must be unboxed.