public static <T> T[] shuffle(T[] a) {
		int N = a.length;
		for (int i = 0; i < N; i++) {
			int r = i + (int) (Math.random() * (N-i));   // between i and N-1
			exch(a, i, r);
		}
		return a;
	}
Check the string is empty.

@param str	string
@return true if empty
ngrinder-runtime/src/main/java/org/ngrinder/dns/DnsUtils.java