Java Utililty Methods Random String

Random r = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < len; i++) {
    char c;
    if (ascii_only) {
        c = (char) r.nextInt(62);
        if (c < 10) {
            c = (char) (48 + c);
...

Random rnd = new Random(System.currentTimeMillis());
String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
StringBuilder b = new StringBuilder();
for (int i = 0; i < lenght; i++) {
    b.append(alpha.charAt(rnd.nextInt(alpha.length())));
return b.toString();

if (length <= 0) {
    return "";
char[] randomChar = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'q', 'w', 'e', 'r', 't', 'y', 'u',
        'i', 'o', 'p', 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'z', 'x', 'c', 'v', 'b', 'n', 'm' };
Random random = new Random();
StringBuffer stringBuffer = new StringBuffer();
for (int i = 0; i < length; i++) {
...

Random random = new Random();
StringBuffer sb = new StringBuffer();
if (length < 1) {
    length = 1;
String base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
for (int i = 0; i < length; i++) {
    int number = random.nextInt(base.length());
...

char[] values = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
        's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
        'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5',
        '6', '7', '8', '9' };
Random random = new Random();
StringBuffer stringBuf = new StringBuffer();
for (int i = 0; i < length; i++) {
    stringBuf.append(values[Math.abs(random.nextInt()) % (values.length)]);
...

if (length <= 0)
    length = 8;
byte[] bytes = new byte[length];
random.nextBytes(bytes);
StringBuffer sb = new StringBuffer(length);
for (int i = 0; i < length; i++) {
    sb.append(m_alphanumeric[Math.abs(bytes[i] % 36)]);
return sb.toString();

char[] text = new char[length];
for (int i = 0; i < length; i++) {
    text[i] = CHARACTERS.charAt(random.nextInt(CHARACTERS.length()));
return new String(text);

char[] chars = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
Random random = new Random();
StringBuilder stringBuiler = new StringBuilder();
for (int i = 0; i < length; i++) {
    stringBuiler.append(chars[Math.abs(random.nextInt()) % 16]);
return stringBuiler.toString();

char[] charaters = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
        'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
return getRandomString(length, charaters);

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