public class Main {
    
    public Main(){
        System.out.println(hasNumbers("StackOverflow"));
        System.out.println(hasNumbers("5t4ck0verfl0w"));
    }
    
    public boolean hasNumbers(final String string){
        String numbers = "0123456789";
        for(char a : string.toCharArray())
            for(char b : numbers.toCharArray())
                if(a == b)
                    return true;
        return false;
    }
    
    public static void main(String[] args) {
        new Main();
    }
}