import java.util.HashMap;
import java.util.Scanner;

public class Xhaeneing {

static int calculate(int a, int b, String oper) {

    int result=0;
    switch (oper) {
    case "+":
        result = a+b;
        break;
    case "-":
        result = a-b;
        break;
    case "*":
        result = a*b;
        break;

    default:
        break;
    }
    return result;
}

static int stringToInt(String a, String b, String oper) {
    int x=0;
    int y=0;

    if(a.equals("zero"))
        x=0;
    if(a.equals("one"))
        x=1;
    if(a.equals("two"))
        x=2;
    if(a.equals("three"))
        x=3;
    if(a.equals("four"))
        x=4;
    if(a.equals("five"))
        x=5;
    if(a.equals("six"))
        x=6;
    if(a.equals("seven"))
        x=7;
    if(a.equals("eight"))
        x=8;
    if(a.equals("nine"))
        x=9;
    if(a.equals("ten"))
        x=10;

    if(b.equals("zero"))
        y=0;
    if(b.equals("one"))
        y=1;
    if(b.equals("two"))
        y=2;
    if(b.equals("three"))
        y=3;
    if(b.equals("four"))
        y=4;
    if(b.equals("five"))
        y=5;
    if(b.equals("six"))
        y=6;
    if(b.equals("seven"))
        y=7;
    if(b.equals("eight"))
        y=8;
    if(b.equals("nine"))
        y=9;
    if(b.equals("ten"))
        y=10;

    return calculate(x,y,oper);

}

static String intToString(int a) {
    String x=null;

    if(a==0)
        x="zero";
    if(a==1)
        x="one";
    if(a==2)
        x="two";
    if(a==3)
        x="three";
    if(a==4)
        x="four";
    if(a==5)
        x="five";
    if(a==6)
        x="six";
    if(a==7)
        x="seven";
    if(a==8)
        x="eight";
    if(a==9)
        x="nine";
    if(a==10)
        x="ten";

    return x;
}

static boolean sort(String result, String answer) {
    /////////////////reedff  erdeff
    HashMap<Character, Integer> hash = new HashMap<Character, Integer>();
    HashMap<Character, Integer> hash2 = new HashMap<Character, Integer>();

// System.out.println("result = "+result.length() +" answer = "+answer.length());
if(result.length() == answer.length()){
for(int x=0;x<result.length();x++){

if(hash.get(result.charAt(x)) == null){
                hash.put(result.charAt(x), 1);
            }
            else if(hash.get(result.charAt(x)) != null)
                hash.put(result.charAt(x), hash.get(result.charAt(x))+1);

            if(hash2.get(answer.charAt(x)) == null){
                hash2.put(answer.charAt(x), 1);
            }
            else if(hash2.get(answer.charAt(x)) != null)
                hash2.put(answer.charAt(x), hash2.get(answer.charAt(x))+1);
        }
        return hash.equals(hash2);
    }
    else
        return false;

}

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int num = sc.nextInt();
    int a=0;
    boolean[] flag = new boolean[num];

    while(a<num){
        String arr1 = sc.next();
        String oper = sc.next();
        String arr2 = sc.next();
        sc.next();
        String ans = sc.next();

        int result1 = stringToInt(arr1, arr2, oper);
        String result2 = intToString(result1);

        flag[a] = sort(result2, ans);

        a++;
    }
    for(boolean out:flag){
        if(out==true)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
}

}

먼저 이클립스에서는 실행이 되는데 여기서는 런타임 오류가 나네요ㅜㅜ어떠한 부분에서 오류가 나는지 궁금합니다.

두번째로 구조적으로 문제가 있는지 그리고 더 좋은 로직을 짤려면 어떠한 방식으로 접근하는지가 좋은지 궁금합니다.
그럼 수고하세요:)