code: public String getAttribute(String name, String defaultValue)
    {
      Params.notNullOrEmpty(name, "Attribute name");
      return getAttribute(name, String.class, defaultValue);
    }
docs: Get attribute value or given default value if there is no attribute with requested name. If given default value is
  null and attribute is not found this method still returns null, that is, requested default value.
  
  @param name attribute name.
  @param defaultValue default value, null or empty accepted.
  @return attribute value or default value.
  @throws IllegalArgumentException if <code>name</code> argument is null or empty.