Set 轻松解决

import java.util.*;

public class Main {

    public Main() {
    }

    public boolean isAllCharExist(String pShortString, String pLongString) {
        Set<Character> set = new HashSet<>();
        for (char ch : pLongString.toCharArray()) {
            set.add(ch);
        }
        for (char ch : pShortString.toCharArray()) {
            if (!set.contains(ch)) {
                return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
        Main solution = new Main();
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            String pShortString = in.nextLine();
            String pLongString = in.nextLine();
            boolean res = solution.isAllCharExist(pShortString, pLongString);
            System.out.println(res);
        }
    } 
}