GameObject java

Main.java

static class GameObject
    {
        private Map<Class<?>, List<Number>> componentsByClass = new HashMap<>();

        public void AddComponent(Class<? extends Number> componentClass) throws IllegalAccessException, InstantiationException
        {
            if (componentClass != null)
            {
                List<Number> components;
                if ((components = componentsByClass.get(componentClass)) == null)
                {
                    components = new ArrayList<>();
                    componentsByClass.put(componentClass, components);
                }

                components.add(componentClass.newInstance());
            }
        }

        public <T extends Number> T GetComponent(Class<T> clazz)
        {
            final List<Number> components = componentsByClass.get(clazz);

            return (T)components.get(0);
        }

        public <T extends Number> List<T> GetComponents(Class<T> clazz)
        {
            final List<Number> components = componentsByClass.get(clazz);

            return (List<T>)Collections.unmodifiableList(components);
        }
    }