Menghitung Frekuensi data yang diinput Java Netbeans

package frekuensidata;

import java.util.Scanner;

public class Main {

public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        String temp = "";

        System.out.print("Masukkan kata : ");

        String input = sc.nextLine().toLowerCase();

        for(int i = 0; i < input.length(); i++){

            boolean exist = false;

            for (int j = 0; j < temp.length(); j++){

                if(input.charAt(i)==temp.charAt(j)){

                    exist = true;

                }

            }

            if(!exist){

                temp = temp + input.charAt(i);

            }

        }

        System.out.println();

        System.out.println("Himpunan huruf dari inputan : "+temp);

        System.out.println();

        System.out.println("Frekuensi  huruf :");

        for (int i = 0; i < temp.length(); i++){

            int sum = 0;

            for(int j = 0; j < input.length(); j++){

                if(temp.charAt(i)==input.charAt(j)) sum++;

            }

            if(temp.charAt(i)==' ') System.out.println(" = "+sum);

            else System.out.println(temp.charAt(i)+" = "+sum);

}

}

}