How can I instantiate an abstract class to remove a NullPointerException?

Question

So the question title is a little weird but it is the only way I could think of the get the point across. I have a NullPointerException from doing this (The extra code is taken out):

public abstract class Generator extends SimpleApplication{

    private static SimpleApplication sa;

    public static void Generator(){
        CubesTestAssets.initializeEnvironment(sa);
    }

I know that the private static SimpleApplication sa; is null but when I instantiate it I get this error instead of a NullPointerException :

SimpleApplication is abstract; cannot be instantiated

I am using the jMonkey Engine 3. If anyone knows how I could solve this problem, that would be great! Thanks!

Answer 1

If you take a close look at the JMonkey documentation, SimpleApplication is made to be extended by you to create your application.

You should create a new class that extends SimpleApplication and implement the missing methods. You then instantiate your custom class and pass it as a parameter.

A little like this :

public class myCustomSimpleApplication extends SimpleApplication {

    // Implementing the missing methods
    @Override
    public void simpleInitApp() {
    }

    @Override
    public void simpleUpdate(float tpf) {
    }

    // etc...

}

And then...

private static SimpleApplication sa = new myCustomSimpleApplication();

public static void Generator(){
    CubesTestAssets.initializeEnvironment(sa);
}