Java Utililty Methods Random String

char[] vals = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'Q', 'W', 'E', 'R', 'T', 'Z', 'U', 'I',
        'O', 'P', 'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', 'Y', 'X', 'C', 'V', 'B', 'N', 'M' };
String randomString = "";
java.util.Random rand = new java.util.Random();
for (int i = 0; i < size; i++)
    randomString += vals[rand.nextInt(size)];
return randomString;

StringBuilder s = new StringBuilder(size);
int len = CHARS.length;
for (int i = 0; i < size; i++) {
    int x = RANDOM.nextInt();
    s.append(CHARS[(x < 0 ? -x : x) % len]);
return s.toString();

String randomString;
char[] chars = "abcdefghijklmnopqrstuvwxyz".toCharArray();
StringBuilder sb = new StringBuilder();
Random random = new Random();
for (int i = 0; i < size; i++) {
    char c = chars[random.nextInt(chars.length)];
    sb.append(c);
randomString = sb.toString();
return randomString;

StringBuffer buffer = new StringBuffer();
Random random = new Random();
for (int i = 0; i < strLength; ++i) {
    int charInt;
    char c;
    if (random.nextBoolean()) {
        charInt = 48 + random.nextInt(10);
        c = (char) charInt;
...

StringBuilder s = new StringBuilder();
int length = minLen + random.nextInt(maxLen - minLen + 1);
for (int i = 0; i < length; i++) {
    s.append(getRandomChar(random, i == 0));
return s.toString();

String randomSection = "";
int r;
if (totalLength < randomSectionLength) {
    randomSectionLength = totalLength;
if (randomSectionLength <= 0) {
    throw new IllegalArgumentException("invalid length " + randomSectionLength);
for (int i = 0; i < randomSectionLength; i++) {
    r = random.nextInt(122);
    if (r >= 0 && r <= 25) {
        r += 65;
    } else if (r >= 26 && r <= 47) {
        r += 71;
    } else if (r >= 58 && r <= 64) {
        r += 10;
    } else if (r >= 91 && r <= 96) {
        r += 10;
    randomSection += ((char) r);
if (totalLength == randomSectionLength) {
    return randomSection;
} else if (totalLength > randomSectionLength) {
    char[] src = randomSection.toCharArray();
    int sections = totalLength / randomSectionLength;
    char[] buffer = new char[totalLength];
    for (int i = 0; i < sections; i++) {
        System.arraycopy(src, 0, buffer, i * randomSectionLength, randomSectionLength);
    int rest = totalLength - sections * randomSectionLength;
    System.arraycopy(src, 0, buffer, sections * randomSectionLength, rest);
    return new String(buffer);
throw new RuntimeException("NOT YET IMPLEMENTED");

int len = rnd.nextInt(maxLength - minLength + 1) + minLength;
char[] data = new char[len];
for (int i = 0; i < data.length; i++) {
    data[i] = (char) (rnd.nextInt(0x7fff) + 1);
return new String(data);

if (paramLength < 1) {
    throw new IllegalArgumentException("paramLength must be positive");
StringBuilder stringBuilder = new StringBuilder(paramLength);
Random random = new Random();
for (int j = 0; j < paramLength; j++) {
    stringBuilder.append(paramString.charAt(random.nextInt(paramString.length())));
return stringBuilder.toString();

if (length == 0) {
    length = 32;
String base = "abcdefghijklmnopqrstuvwxyz0123456789";
Random random = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
    int number = random.nextInt(base.length());
...

if (random == null) {
    random = new Random();
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss-SS");
String dateStr = formatter.format(new Date());
return String.format("%s_%d", dateStr, (int) (random.nextFloat() * 1000));