Collision pairs

import java.util.ArrayList;
public class Collision {
    private static ArrayList<Collision> POOL = new ArrayList<Collision>();
    public GameObject mA;
    public GameObject mB;

    public static Collision init(GameObject a, GameObject b) {
        if (POOL.isEmpty()) {
            return new Collision(a, b); //added to the pool on release
        }
        Collision c = POOL.remove(0);
        c.mA = a;
        c.mB = b;
        return c;
    }

    public static void release(Collision c) {
        c.mA = null;
        c.mB = null;
        POOL.add(c);
    }

    public boolean equals(Collision c) {
        return (mA == c.mA && mB == c.mB) || (mA == c.mB && mB == c.mA);
    }

    public Collision(GameObject a, GameObject b) {
        mA = a;
        mB = b;
    }
}