Why does copying a Java object only make a shallow copy?

When I assign one variable containing a Java object to another and make changes to the original object, both are changed. Why is this?

Answer 1

[MathWorks Support Team]

Copying a Java object only makes a shallow copy of the object. A new Java object of A's class is not created. So if you have a Java object A, the command:

    B = A;

creates B as a reference to A. Any change in A will be reflected in B, and vice versa. This is because A and B actually refer to the same Java object.

In order to make a deep copy of A, you need to invoke a cloning method for the class if one is defined.