BulletSystem.java

@Subscribe
    void handleEvent(WeaponFiredEvent event) {
        Vector2 position = positionComponentMapper.get(playerSystem.getPlayer().getId()).getPosition();
        Entity bullet = EntityFactory.createBullet(world, position.x, position.y);
        bullets.add(bullet);
        PhysicsComponent physicsComponent = physicsComponentMapper.get(bullet.getId());
        PositionComponent positionComponent = positionComponentMapper.get(bullet.getId());

        BodyDef bodyDef = new BodyDef();
        bodyDef.type = BodyDef.BodyType.DynamicBody;

        // Set our body to the same position as our sprite
        bodyDef.position.set(positionComponent.getPosition().x-24, positionComponent.getPosition().y+12);
        bodyDef.fixedRotation = true;
        // Create a body in the world using our definition
        Body body = physicsSystem.getPhysics().createBody(bodyDef);
        physicsComponent.setBody(body);
        body.setBullet(true);
        body.setGravityScale(0);
        body.setLinearDamping(0);


        CircleShape shape = new CircleShape();
        shape.setRadius(1);


        FixtureDef fixtureDef = new FixtureDef();
        fixtureDef.shape = shape;
        fixtureDef.density = 1f;
        fixtureDef.friction = 0;

        physicsComponent.setFixture(physicsComponent.getBody().createFixture(fixtureDef));

        body.applyLinearImpulse(new Vector2(-10000000f, 0), body.getWorldCenter(), false);

        // Shape is the only disposable of the lot, so get rid of it
        shape.dispose();
    }

PhysicsSystem.java

    @Override
    protected void initialize() {
        physics = new World(new Vector2(0, 0), true);
        physics.setContactListener(new CollisionHandler());
    }