can't figure out initialization error - java

Question

I can not for the life of me figure out why I'm getting a "variable key might not have been initialized" error. I've entered my entire code because if I remove the BufferedReader and set the string equal to I don't get the error. Also, if I leave the BufferedReader part in and remove the StringBuffer part, string key initializes just fine. Please help! New to java (and programming in general).

import java.util.*;
import java.io.*;

public class reverseString {
    public static void main(String [] args) {
        String abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String cipher = "";
        String input = "";
        String newCipher;
        String ouput = "";

        BufferedReader readerKeyword = null;
        String key;
        try {
            readerKeyword = new BufferedReader(new FileReader("keyword.txt"));          
        } catch (FileNotFoundException fnfex) {
            System.out.println(fnfex.getMessage() + " File not found.");
            System.exit(0); 
        }
        try {
            while ((key = readerKeyword.readLine()) !=null) {
                System.out.println(key);
            }
        } catch (IOException ioex) {
            System.out.println(ioex.getMessage() + " Unable to read file.");
            System.exit(0);
        }

        StringBuffer sb = new StringBuffer();
        int len = abc.length();
        for(int i = len -1;i>=0;i--)
            cipher = cipher + abc.charAt(i);
        System.out.println(abc);
        System.out.println(cipher);
        newCipher = sb.append(key + cipher).toString();
        System.out.println(newCipher);
        System.out.println(removeDuplicates(newCipher));
   }

   static String removeDuplicates(String newCipher) {
       char[] charArr = newCipher.toCharArray();
       Set<Character> charSet = new LinkedHashSet<Character>();
       for(char ch : charArr) {
           charSet.add(ch);
       }
       StringBuffer StrBuf = new StringBuffer();
       for(char c : charSet) {
           StrBuf.append(c);
       }
       return StrBuf.toString();
   }
}

Was is not initialized in the while loop at line28?

Answer 1

IDE and Compiler shows it when it is not guaranteed initialization for safety/precaution. Do this and it should go away,

BufferedReader readerKeyword = null;
String key = null;

However, do make sure that it gets initialized.

It is not guaranteed initialization because it is inside a try-catch block and if you get an exception, you can get by without initialization because, you are handling it.