Text Processing - Valid user names

import java.util.Scanner;

public class ValidUsernames {
    public static void main(String[] args) {
        Scanner myScan=new Scanner(System.in);
        String [] usernames=myScan.nextLine().split(", ");
        for (int i = 0; i <usernames.length ; i++) {
            boolean hasLength=checkLenght(usernames[i]);
            boolean containsRightSymbols=checkSymbols(usernames[i]);
            if (hasLength&&containsRightSymbols){
                System.out.println(usernames[i]);
            }
        }
    }

    private static boolean checkSymbols(String username) {
        boolean isIn=false;
        for (int i = 0; i <username.length() ; i++) {
            if (username.charAt(i)==45||(username.charAt(i)>=48&&username.charAt(i)<=57)||(username.charAt(i)>=65&&username.charAt(i)<=90)||username.charAt(i)==95||(username.charAt(i)>=97&&username.charAt(i)<=122)){
                isIn=true;
            } else{
                isIn=false;
                break;
            }
        }
        if (isIn){
            return true;
        }
        return false;
    }

    private static boolean checkLenght(String username) {
        if (username.length()>=3&&username.length()<=16){
            return true;
        }
        return false;
    }
}