Can PowerMock mock system classes like System or Math?

Can PowerMock mock system classes like System or Math?

Answer:

Explanation:

Yes, PowerMock can mock system classes like System or Math. PowerMock’s ability to modify bytecode at runtime allows it to mock even final system classes, which are usually unmockable in other frameworks.

For example:

mockStatic(System.class);
when(System.currentTimeMillis()).thenReturn(123456789L);

In this example, the static method currentTimeMillis() in the System class is mocked to return a specific value.

Reference links:

https://www.javaguides.net/p/top-java-libraries.html