Generate Random List Length?

I have my code which will generate a random string using an ArrayList. However, I aso want to have it generate them in random lengths, not just using all the chars and numbers.

public static void main(String[] args) {
String[] CHARS = {"A","B","C","D","E","F","G",
"H","I","J","K","L","M","N",
"O","P","Q","R","S","T","U",
"V","W","X","Y","Z","1","2",
"3","4","5","6","7","8","9","0"};
List<String> pass = Arrays.asList(CHARS);
Collections.shuffle(pass);
for (String chars : pass) {
System.out.print(chars);
}
}