public String getNextString(int min, int max) {
    int length = getNextInt(min, max);

    StringBuilder strbld = new StringBuilder();
    for (int i = 0; i < length; i++) {
      char ch = validChars.charAt(rand.nextInt(validChars.length()));
      strbld.append(ch);
    }

    return strbld.toString();
  }
Simple utility to generate random values.
samza-tools/src/main/java/org/apache/samza/tools/RandomValueGenerator.java