Java Utililty Methods Random String

String chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
Random rand = new Random();
StringBuilder value = new StringBuilder();
int charsLength = chars.length() - 1;
for (int i = 0; i < length; i++) {
    value.append(chars.charAt(rand.nextInt(charsLength)));
return value.toString();
...

String base = "abcdefghijklmnopqrstuvwxyz0123456789";
return getRandomString(base, length);

Random r = new Random();
char min = 48;
char max = 122;
String ranStr = "";
for (int i = 0; i < length; i++) {
    char c = (char) (r.nextInt(max - min + 1) + min);
    ranStr += c;
return ranStr;

StringBuffer bu = new StringBuffer();
String[] arr = { "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j",
        "k", "m", "n", "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", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };
Random random = new Random();
while (bu.length() < length) {
    String temp = arr[random.nextInt(57)];
    if (bu.indexOf(temp) == -1) {
...

Random random = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
    int number = random.nextInt(3);
    long result = 0;
    switch (number) {
    case 0:
        result = Math.round(Math.random() * 25 + 65);
...

StringBuffer buffer = new StringBuffer("0123456789abcdefghijklmnopqrstuvwxyz");
StringBuffer sb = new StringBuffer();
Random r = new Random();
int range = buffer.length();
for (int i = 0; i < length; i++) {
    sb.append(buffer.charAt(r.nextInt(range)));
return sb.toString();
...

char[] data = new char[length];
Random random = new Random();
for (int i = 0; i < length; i++) {
    data[i] = baseData[random.nextInt(baseDataLength)];
return new String(data);

StringBuffer r = new StringBuffer(length);
String src = src_all;
for (int i = 0; i < length; i++) {
    r.append(getRandomStr(src));
return r.toString();

if (length <= 0) {
    length = 10;
char[] pattern = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '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' };
StringBuilder result = new StringBuilder();
int n = pattern.length;
...

StringBuffer retObj = new StringBuffer();
String letters = "abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789";
Random random = new Random(System.currentTimeMillis());
for (int i = 0; i < length; i++) {
    int pos = random.nextInt(letters.length());
    retObj.append(letters.charAt(pos));
return retObj.toString();
...