Disposing objects when changing screens [closed]

Possible memory leak. LibGDX uses native Box2D. To use it, they wrote Java wrapper, because of that, the objects that are created by the native methods need manual disposal.

    FixtureDef fixtureDef = new FixtureDef();
    fixtureDef.shape = shape;
    fixtureDef.density = 1f;
    Fixture fixture = body.createFixture(fixtureDef);
    shape.dispose(); // You need to dispose Shape manually...

Also do not forget to dispose the world.

@Override
public void dispose() {
    //dispose other stuff
    world.dispose();
}

Also, if more detailed profiling is not possible, comment some part and check it again ....

Setting objects to null might not guarantee proper disposal. Usually an asset manager has some kind of reference counter for every used asset. It is better to use dispose instead of setting to null and waiting until the destructor call happens via garbage collector. It is better because the dispose happens instant and you have better control when memory is freed and stuttering can occur on large disposals. Understand that if you dispose the asset manager clears cpu and gpu memory for e.g. a texture. Initializing all screens is only a good idea if your game size is very small and you want achieve faster level switching. Otherwise it is a bad practice because you waste system resources for content that isn't even consumed by the player. The general rule is to only allocate as much as absolutely required and as less as possible. That's the whole point of loading screens. Less memory allocated = able to support older hardware = bigger playerbase.