'new' modifier in Java

Question

Is there an equivalent to C#'s 'new' modifier in Java?

I'd like to use it for unit tests - every init() method should be marked final and annotated with @Before. Then, jUnit executes all of these init() methods.

I don't want to bother coming up with new names for each of these init() methods, and I definitely wants to mark them as final to make sure they don't override eachother (an alternative pattern is to override and call super.init() from every init() method).

Answer 1

Unfortunately not. Heck, before @Override there wasn't even any way of protecting against typos when overriding.

You can't create a method with the same signature as a superclass method without it overriding that method. Admittedly I try not to do this even in C#...

Have you considered using initFoo and initBar for classes Foo and Bar respectively (etc)? It's a simple enough pattern to follow, and would avoid the name collisions. A bit ugly, admittedly.

Answer 2

Java does not have an equivalent to the C# new operator which is

Used to hide an inherited member from a base class member.

For what you'd like to do, why not create a base class that your other tests can extend, and create an abstract method named init() (marked with @Before) in the base class? This forces all subclasses to supply an init() method.

Answer 3

A common pattern is to make your own 'before' methods final and create protected (abstract) methods for the subclasses.

In the superclass

@Before
public final void before() {
   onBefore();
}

protected void onBefore()  {

}

In the subclass

protected void onBefore() {
    // prepare the test fixture
}

This gives you the best of both worlds:

• a well-known method to override in sub-classes;
• overriding is optional;
• the superclass method is never overriden;
• the client method is invoked when the super-class decides, i.e. either before or after the super-class decides.

It does have a single downside - it ties you to a single super-class. Still, that may not be an issue to your environment.