src/main/java/com/zandero/utils/KeyGenerator.java
public static String generateString(int length) {

		if (length <= 0 || length > 100) {
			throw new IllegalArgumentException("Can't generate random id with length: " + length);
		}

		SecureRandom random = new SecureRandom();
		StringBuilder sb = new StringBuilder(length);
		for (int i = 0; i < length; i++) {
			sb.append(ELEMENTS.charAt(random.nextInt(ELEMENTS.length())));
		}

		return sb.toString();
	}
public static String generateString(int length) {

		if (length <= 0 || length > 100) {
			throw new IllegalArgumentException("Can't generate random id with length: " + length);
		}

		SecureRandom random = new SecureRandom();
		StringBuilder sb = new StringBuilder(length);
		for (int i = 0; i < length; i++) {
			sb.append(ELEMENTS.charAt(random.nextInt(ELEMENTS.length())));
		}

		return sb.toString();
	}
Generates random string from ELEMENTS set of chars and numbers

@param length desired length of key greater than 0
@return random string of desired length (min 1, max 100 characters long)