Java Program to generate random numbers string

public class Demo {
	static char num[] = { '0', '1', '2', '3', '4', '5' };
	public static char randomNum() {
		return num[(int) Math.floor(Math.random() * 5)];
	}
	public static void main(String[] args) {
		int len = 5;
		StringBuilder strBuilder = new StringBuilder();
		for (int i = 0; i<len; i++) {
			strBuilder.append(randomNum());
		}
		System.out.println("Random numbers string = "+strBuilder.toString());
	}
}