code: public static String concat(Object... objects)
    {
      StringBuilder sb = new StringBuilder();
      for(Object object : objects) {
        if(object != null) {
          sb.append(object);
        }
      }
      return sb.toString();
    }
docs: Concatenates a variable number of objects, as strings. For every given argument, convert it to string using
  {@link Object#toString()} overload and append to concatenated result. If a given argument happens to be null, skip
  it. Return empty string if this method is invoked with no arguments at all.
  
  @param objects variable number of objects.
  @return concatenated objects.