Java Utililty Methods Random Number

Random random = new Random();
StringBuilder sb = new StringBuilder(randomCount);
for (int i = 0; i < randomCount; i++)
    sb.append((char) ('0' + random.nextInt(10)));
return sb.toString();

Random randomGenerator = new Random();
long range = (long) startNumber - (long) endNumber + 1;
long fraction = (long) (range * randomGenerator.nextDouble());
int randomNumber = (int) (fraction + startNumber);
return (Math.abs(randomNumber) == 0) ? getRandomNumber(startNumber, endNumber) : Math.abs(randomNumber);

return useRandomForNumberBetween(rand, min, max);

return 1000000000L + generator.nextInt(2000000000);

return new Random(++seedQualifier + System.nanoTime());

return min + random.nextInt(max - min + 1);

if (count > range) {
    return null;
if (count < 0 || range < 0) {
    return null;
ArrayList<Integer> indices = new ArrayList<Integer>();
if (count < range / 2) {
...

Random rand = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
    int pos = rand.nextInt(NUMBERS.length());
    sb.append(NUMBERS.charAt(pos));
return sb.toString();

if (length > 9 || length < 1) {
    return null;
int maxNum = (int) Math.pow(10, length);
Random random = new Random(System.currentTimeMillis());
int code = random.nextInt(maxNum - 1);
return String.format("%0" + length + "d", code);

String str = new String();
for (int j = 0, n = R.nextInt(maxlen) + 1; j < n; ++j) {
    str += (char) ('0' + R.nextInt(10));
return str;