What is the difference between mocking and spying in Java?

What is the difference between mocking and spying in Java?

In Java, mocking creates a fake object that simulates the behavior of a real object, while spying allows you to track interactions with a real object.

Can you give me an example of when to use mocking?

Sure! Use mocking when you want to isolate a unit of code and test it without relying on external dependencies.

And when should I use spying instead?

Spying is useful when you want to verify interactions with a real object, such as checking if a method was called.

Are there any libraries in Java that support mocking and spying?

Yes, popular libraries include Mockito and JMockit, which provide features for both mocking and spying.