Java: Print a unique character in a string

Question

I\'m writing a program that will print the unique character in a string (entered through a scanner). I\'ve created a method that tries to accomplish this but I keep getting

Answer 1

The accepted answer will not pass all the test case for example

input -"aaabcdd"

desired output-"bc"
but the accepted answer will give -abc

because the character a present odd number of times.

Here I have used ConcurrentHasMap to store character and the number of occurrences of character then removed the character if the occurrences is more than one time.

import java.util.concurrent.ConcurrentHashMap;

public class RemoveConductive {

    public static void main(String[] args) {

        String s="aabcddkkbghff";

        String[] cvrtar=s.trim().split("");

        ConcurrentHashMap hm=new ConcurrentHashMap<>();
        for(int i=0;i1){
                hm.remove(ele);
            }
        }
        for(String key:hm.keySet()){
            System.out.print(key);
        }
    }  
}