Generate UUID in Java

generateUUID.java

public class Main {
    /**
     * Generates a random UUID (Universally Unique Identifier) in the format:
     * xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where 'x' represents a random
     * hexadecimal digit
     * and 'y' represents a random hexadecimal digit with the 13th character set to
     * '4' (version 4 UUID).
     *
     * @return The generated UUID as a string.
     */
    public static String createUUID() {
        String format = "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx";
        StringBuilder uuid = new StringBuilder(format);
        for (int i = 0; i < format.length(); i++) {
            if ((Character.compare(format.charAt(i), 'x') == 0) || (Character.compare(format.charAt(i), 'y') == 0)) {
                uuid.setCharAt(i, getRandomHexDigit(format.charAt(i)));
            }
        }
        return uuid.toString();
    }

    /**
     * Generates a random hexadecimal digit between 0 and 15.
     *
     * @param character The character 'x' or 'y' from the UUID format.
     *                  If 'x', the generated digit can be any hexadecimal digit
     *                  (0-9, a-f).
     *                  If 'y', the generated digit must have the 13th character set
     *                  to '4' (version 4 UUID).
     * @return The random hexadecimal digit as a char.
     */
    private static char getRandomHexDigit(char character) {
        int random = (int)(Math.random() * 16);
        int value = character == 'x' ? random : (random & 0x3) | 0x8; // Ensure the 13th character is '4' (version 4 UUID)
        return Integer.toHexString(value).charAt(0);
    }

    public static void main(String[] args) {
        System.out.println(createUUID());
    }
}