Java generate random string

	/**
	 * parent string
	 */
	private static String string = "abcdefghijklmnopqrstuvwxyz";    

	/* ********************************************
	 * method name   : getRandom
	 * description : Generate 1-count random numbers
	 * @return       : int
	 * @param        : @param count
	 * @param        : @return
	 * modified      : ncc ,  2017-11-24
	 * @see          :
	 * ********************************************/      
	private static int getRandom(int count) {
	    return (int) Math.round(Math.random() * (count));
	}


	/* ********************************************
	 * method name   : getRandomString
	 * description : generate a random string
	 * @return       : String
	 * @param        : @param length
	 * @param        : @return
	 * modified      : ncc ,  2017-11-24
	 * @see          :
	 * ********************************************/      
	private static String getRandomString(int length){
	    StringBuffer sb = new StringBuffer();
	    int len = string.length();
	    for (int i = 0; i < length; i++) {
	        sb.append (string.charAt (getRandom (len-1)));
	    }
	    return sb.toString();
	}
	
	public static void main(String[] args) {
		int len ​​= getRandom(6) + 6;
		String str = getRandomString (len);
		System.out.println(str);
	}

   A string of 6 to 12 digits can be randomly generated.