Solution to find All Check Digits in Java

ACES.txt File

100532P
300563X
500562Y
604532X
875300M
456231P
560340M
103562F

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PROGRAM

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.HashSet;
import java.util.Set;


public class CountChkDgt {

	public static void main(String[] args) {
		try {
			Set hset=new HashSet();
			BufferedReader br=new BufferedReader(new FileReader("./ACES.txt"));
			String ss="";
			String chk="";
			while(true){
				ss=br.readLine();
				if(ss==null){
					break;
				}
				chk=ss.substring(6, 7);
				hset.add(chk);				
			}
			for(String val: hset){
				System.out.println(val);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}

	}

}

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OUTPUT

F
P
M
Y
X