What's the difference between using @BeforeClass and using instance or static variable in JUnit 4 Java?

Question

I'm new to unit test. About the purpose of using @Before annotation in JUnit 4. I just don't know the point of using it:

public class FoodTestCase {
    static private Food sandwich;

    @BeforeClass
    public static void initialise(){
        sandwich = new Sandwich();    
    }

}

vs

public class FoodTestCase {
    static private Food sandwich = new Sandwich();

}

What's the difference?

Answer 1

In this case it may not be necessary, as the initialization is really simple.

In case you have some logging, complex initialization or need to free some resources, you have to use @BeforeClass and @AfterClass