code: public static void checkStringListArgument(List<String> str, String variableName) {
      if (null == str) {
        throw new NullPointerException(ExceptionMessageMap.getMessage("000002")
            + "  { variableName=[" + variableName + "] }");
      }
      if (str.size() == 0) {
        throw new IllegalArgumentException(ExceptionMessageMap.getMessage("000002")
            + "  { variableName=[" + variableName + "] }");
      }
      for (int i = 0; i < str.size(); i++) {
        checkStringArgument(str.get(i), variableName);
      }
    }
docs: Checks a <code>List&lt;String&gt;</code> argument to make sure it is not null, none of its
  elements are null, and all its elements contain one or more characters. If the
  <code>List&lt;String&gt;</code> or a contained <code>String</code> is null, a
  <code>NullPointerException</code> is thrown. If the <code>List&lt;String&gt;</code> or a
  contained <code>String</code> has length zero, an <code>IllegalArgumentException</code> is
  thrown.
  
  @param str
  The <code>List&lt;String&gt;</code> to check.
  @param variableName
  The name of the variable being checked; for use in exception messages.