Pool.java

interface Factory<T> {
    T create();
}

public class Pool<T> {

    private final Factory<T> factory;
    private final Array<T> pool;

    public Pool(Factory<T> factory) {
        this.factory = factory;
        pool = new Array<T>();
    }

    public void clear() {
        pool.clear();
    }

    public T obtain() {
        if (pool.size > 0)
            return pool.pop();

        return factory.create();
    }

    public void release(T t) {
        pool.add(t);
    }
}