Corner Lord

public abstract class Component {

    private Game game;
    private Entity parent;

    protected String tag;

    public Component(Game game, Entity parent) {
        this.game =game;
        this.parent = parent;
    }
    public abstract void tick();
    public abstract void render(Screen screen);

    public Game getGame() {
        return game;
    }
    public void setGame(Game game) {
        this.game = game;
    }
    public Entity getParent() {
        return parent;
    }
    public void setParent(Entity parent) {
        this.parent = parent;
    }
    public String getTag() {
        return tag;
    }
    public void setTag(String tag) {
        this.tag = tag;
    }
}

//

public class AABBComponent extends Component {

    private int centerX, centerY;
    private int halfWidth, halfHeight;

    public AABBComponent(Game game, Entity parent) {
        super(game, parent);
        this.tag = "aabb";
    }

    @Override
    public void tick() {
        double time = 1.0/ 60.0;
        @SuppressWarnings("unused")
        float dt = (float) time;

        centerX = (int) (getParent().getPosX() + (getParent().getWidth() / 2));
        centerY = (int) (getParent().getPosY() + (getParent().getHeight() / 2) + getParent().getPaddingTop() / 2);
        halfWidth = (getParent().getWidth()/2) - getParent().getPadding();
        halfHeight = (getParent().getHeight()/2) - (getParent().getPaddingTop() / 2);

        Physics.addAABBComponent(this);
    }

    @Override
    public void render(Screen screen) {

    }

    public int getCenterX() {
        return centerX;
    }

    public void setCenterX(int centerX) {
        this.centerX = centerX;
    }

    public int getCenterY() {
        return centerY;
    }

    public void setCenterY(int centerY) {
        this.centerY = centerY;
    }

    public int getHalfWidth() {
        return halfWidth;
    }

    public void setHalfWidth(int halfWidth) {
        this.halfWidth = halfWidth;
    }

    public int getHalfHeight() {
        return halfHeight;
    }

    public void setHalfHeight(int halfHeight) {
        this.halfHeight = halfHeight;
    }
}

//

public class Physics {

    private static List<AABBComponent> aabbList = new ArrayList<AABBComponent>();

    public static void addAABBComponent(AABBComponent aabb) {
        aabbList.add(aabb);
    }

    public static void tick() {
        for (int i = 0; i < aabbList.size(); i++) {
            for (int j = i + 1; j < aabbList.size(); j++) {
                AABBComponent c0 = aabbList.get(i);
                AABBComponent c1 = aabbList.get(j);
                if(Math.abs(c0.getCenterX() - c1.getCenterX()) < c0.getHalfWidth() + c1.getHalfWidth()) {
                    if(Math.abs(c0.getCenterY() - c1.getCenterY()) < c0.getHalfHeight() + c1.getHalfHeight()) {
                        c0.getParent().collision(c1.getParent());
                        c1.getParent().collision(c0.getParent());
                    }
                }
            }
        }

        aabbList.clear();
    }
}