Object copy

http://en.wikipedia.org/wiki/Object_copy#Shallow_copy

Shallow copy

One method of copying an object is the shallow copy. In the process of shallow copying A, B will copy all of A’s field values. If the field value is a memory address it copies the memory address, and if the field value is a primitive type it copies the value of the primitive type.

Deep copy

An alternative is a deep copy. Here the data is actually copied over. The result is different from the result a shallow copy gives. The advantage is that A and B do not depend on each other but at the cost of a slower and more expensive copy.

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