public static boolean equals(Object[] a, Object[] a2) {
    if (a==a2)
        return true;

// I thought it's false, maybe we can change it as the comment below
if (a==null || a2==null)
        return false;
/*
if (a==null && a2==null)
        return true;
*/
    int length = a.length;
    if (a2.length != length)
        return false;

    for (int i=0; i<length; i++) {
        Object o1 = a[i];
        Object o2 = a2[i];
        if (!(o1==null ? o2==null : o1.equals(o2)))
            return false;
    }

    return true;
}