static public Object concat(Object a, Object b) {
    Class<?> type = a.getClass().getComponentType();
    int alength = Array.getLength(a);
    int blength = Array.getLength(b);
    Object outgoing = Array.newInstance(type, alength + blength);
    System.arraycopy(a, 0, outgoing, 0, alength);
    System.arraycopy(b, 0, outgoing, alength, blength);
    return outgoing;
  }