code: public static String randomString(final int size) {
          final StringBuilder builder = new StringBuilder();
          while (builder.length() < size) {
              final String suffix = java.util.UUID.randomUUID().toString().replace("-", "");
              builder.append(suffix);
          }
          return builder.substring(0, size);
      }
docs: Return a random string of a certain size.
  
  @param size the size
  @return the random size