Java Utililty Methods Random String

if ((pattern == null) || (pattern.length() == 0)) {
    return "";
final char[] patternChars = pattern.toCharArray();
final StringBuilder retVal = new StringBuilder(pattern.length());
final java.util.Random rndGen = new java.util.Random();
for (char patternChar : patternChars) {
    if (patternChar == '#') {
...

Random random = new Random();
StringBuffer buffer = new StringBuffer();
while (count-- != 0) {
    char ch = (char) (random.nextInt(96) + 32);
    buffer.append(ch);
return buffer.toString();

StringBuilder sb = new StringBuilder(len);
for (int i = 0; i < len; i++)
    sb.append(AB.charAt(random.nextInt(AB.length())));
return sb.toString();

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

Random random = new Random();
if (length < 1) {
    throw new IllegalArgumentException("length < 1: " + length);
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
    int rnd = random.nextInt(10 + 'z' - 'a');
    if (rnd < 10) {
...

int rnd;
final Random r = new Random();
final String sorigen = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz";
final char fuente[] = sorigen.toCharArray();
char buffer[] = new char[length];
for (int i = 0; i < length; i++) {
    rnd = Math.abs(r.nextInt()) % fuente.length;
    buffer[i] = fuente[rnd];
...

StringBuilder str = new StringBuilder();
String base = "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
Random rnd = new Random();
for (int i = 0; i < length; i++) {
    str.append(base.charAt(rnd.nextInt(base.length())));
return str.toString();

String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
int charLength = chars.length();
StringBuilder pass = new StringBuilder(charLength);
for (int x = 0; x < length; x++) {
    int i = (int) (Math.random() * charLength);
    pass.append(chars.charAt(i));
return pass.toString();
...

int blen = ((length + 3) / 4) * 3; 
byte[] bval = new byte[blen];
rnd.nextBytes(bval);
return new String(Base64.getEncoder().encode(bval), 0, length).replace('/', '$');

return generateRandomString(RANDOM_CHARS, length);