Java static methods pros & cons

Question

I havent used a lot of static methods before, but just recently I tend to use more of them. For example if I want to set a boolean flag in a class, or acess one without the need

Answer 1

Is this something i should avoid?

In general, yes. Statics represent global state. Global state is hard to reason about, hard to test in isolation, and generally has higher thread-safety requirements.

If I want to test what happens to an object in a certain state, I can just create the object, put it into that state, perform my tests, and let it get garbage collected.

If I want to test what happens to global state, I need to make sure I reset it all at the end of my test (or possibly at the start of every test). The tests will now interfere with each other if I'm not careful about doing that.

Of course, if the static method doesn't need to affect any state - i.e. if it's pure - then it becomes somewhat better. At that point all you're losing is the ability to replace that method implementation, e.g. when testing something that calls it.