what is boxing and unboxing?

[designpluz]

what is boxing and unboxing?

[eSparkBiz]

If it's the question of C# then,

Boxing is a procedure of converting a value type to an object type. Here, the value type is stored on the stack, and the object type is stored in the heap memory.

Unboxing is a conversion of the object type to the value type. In Unboxing the value of boxed object type stored on the heap is transferred to the value type that is stored on the stack. It is totally inverse of Boxing.

[Ryan Harris]

Java provides additional support for implicitly converting between base types and their wrapper types through a process known as automatic boxing and unboxing.


In any context for which an Integer is expected (for example, as a parameter), int value k can be expressed, in which case Java automatically boxes the int, with an implicit call to new Integer(k).
In reverse, in any context for which int is expected, an Integer value v can be given in which case Java automatically unboxes it with an implicit call to v.intValue(). Similar conversions are made with the other base-type wrappers. Finally, all of the wrapper types provide support for converting back and forth between string literals.

[Piyush Jain]

Boxing is the process of converting a value typr to the type object or to any interface type implemented by this value type. When the CLR boxes a value type, it wraps the value inside a System.Object and stores it on the managed heap.

Unboxing extracts the value type from the object. Boxing is implicit; unboxing is explicit. The concept of boxing and unboxing underlies the C# unified view of the type system in which a value of any type can be treated as an object.

[joe merial]

Boxing is the implicit conversion of a value type to a reference type.

Unboxing is the explicit conversion of the reference type created by boxing, back to a value type.