code: public static String last(final String value, int n) {
          validate(value, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
          if (n > value.length()) {
              return value;
          }
          return value.substring(value.length() - n);
      }
docs: Return the last n chars of String
  
  @param value The input String
  @param n     Number of chars to return
  @return n Last characters