Java Utililty Methods Random String

char[] characters = new char[length];
for (int i = 0; i < length; i++) {
    char start, end;
    switch (random.nextInt(4)) {
    case 0:
        start = 'A';
        end = 'Z';
    case 1:
...

String alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int N = alphabet.length();
Random r = new Random();
StringBuilder sb = new StringBuilder(length);
for (int i = 0; i < length; i++) {
    sb.append(alphabet.charAt(r.nextInt(N)));
return sb.toString();
...

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

Random rngRandom = new Random();
char[] text = new char[length];
int lengRnd = RANDOM_STRING.length();
for (int i = 0; i < length; i++) {
    text[i] = RANDOM_STRING.charAt(rngRandom.nextInt(lengRnd));
return new String(text);

String[] caseList = new String[Length];
if (caseType.toUpperCase().matches("UPPER")) {
    for (int i = 0; i < caseList.length; i++) {
        caseList[i] = "UPPER";
} else if (caseType.toUpperCase().matches("LOWER")) {
    for (int i = 0; i < caseList.length; i++) {
        caseList[i] = "LOWER";
...

String str;
try {
    str = new String(new byte[] {}, charset);
} catch (UnsupportedEncodingException ex) {
    System.err.println("ERROR: Unsupported encoding: " + charset);
    ex.printStackTrace();
    return null;
for (int i = 0; i < length; i++) {
    int rand = (int) (Math.random() * 62);
    if (rand > 9 && rand < 36) {
        rand += 7;
    } else if (rand > 35) {
        rand += 13;
    str += (char) (rand + 48);
return str;

char[] randomString;
String LCaseChars = "abcdefgijkmnopqrstwxyz";
String UCaseChars = "ABCDEFGHJKLMNPQRSTWXYZ";
String NumericChars = "23456789";
String SpecialChars = "*$-+?_&=!%{}/";
Map<String, Integer> charGroupsUsed = new HashMap<>();
charGroupsUsed.put("lcase", minLCaseCount);
charGroupsUsed.put("ucase", minUCaseCount);
...

String alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
int length = alphabet.length();
String s = "";
Random r = new Random(System.currentTimeMillis());
for (int i = 0; i < n; i++)
    s += alphabet.charAt(r.nextInt(length));
return s;

Random rd = new Random();
char lowerChars[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
char upperChars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
char numbers[] = "0123456789".toCharArray();
char specialChars[] = "!$-_+".toCharArray(); 
List<Character> pwdLst = new ArrayList<>();
for (int g = 0; g <= n; g++) {
    for (int z = 0; z < 1; z++) {
...

String random = new String();
Random rand = new Random();
for (int i = 0; i < size; i++) {
    int random_nbr = rand.nextInt(random_str.length());
    random += (rand.nextBoolean()) ? random_str.charAt(random_nbr)
            : Character.toLowerCase(random.charAt(random_nbr));
return random;
...