I have a class X with all static methods. And an app A to test the behavior of this class. I have separate unit tests for both. Note: I have to strictly adhere to writing separate unit tests for both.
Suppressing the static initialization for the class A is affecting unit tests of the class X for which I'm doing mockstatic in class A.
I'm not sure of the scope of @SuppressStaticInitializationFor.
That is the problem when turning to PowerMock to fix problems introduced by unwise usage of static. Keep in mind: static is an abnormality within good OO design - as it breaks (easy) unit testing, polymorphism, and leads to direct coupling of your classes!
So my advise here: simply avoid using static in a way that leads you to ask for PowerMock in order to do unit testing. In other words: instead of using PowerMock, learn how to create testable code (you can start here)) and then create production code that can be tested with Mockito or EasyMock ... without any super Powers needed.
If you can't do that: at the very minimum, make sure that you never create static init code that breaks your unit test environment. It is a fair request to your development team to come up with production classes that can at least be loaded by JUnit tests.