How does Cloneable work in Java and how do I use it?

Question

I would like to know the following:

1. Cloneable means we can have a clone or a copy of objects, by implementing the Cloneable interface. What are the advantages and disadvantages of doing that?
2. How does the recursive cloning happen if the object is a composite object?

Answer 1

The first thing you should know about Cloneable is - don't use it.

It is very hard to implement cloning with Cloneable right, and the effort is not worth it.

Instead of that use some other options, like apache-commons SerializationUtils (deep-clone) or BeanUtils (shallow-clone), or simply use a copy-constructor.

See here for the views of Josh Bloch about cloning with Cloneable, which explains the many drawbacks of the approach. (Joshua Bloch was a Sun employee, and led the development of numerous Java features.)