Match Function in Java

public static Cons dummysub = list(list("t", "t"));

public static Cons match(Object pattern, Object input) {
    return matchb(pattern, input, dummysub); }

public static Cons
  matchb(Object pattern, Object input, Cons bindings) {
    if ( bindings == null ) return null;
    if ( consp(pattern) )
        if ( consp(input) )
            return matchb( rest( (Cons) pattern),
                           rest( (Cons) input),
                           matchb( first( (Cons) pattern),
                                   first( (Cons) input),
                                   bindings) );
        else return null;
    if ( varp(pattern) ) {
        Cons binding = assoc(pattern, bindings);
        if ( binding != null )
            if ( equal(input, second(binding)) )
                return bindings;
            else return null;
        else return cons(list(pattern, input), bindings); }
    if ( eql(pattern, input) )
        return bindings;
    return null; }