Replace cipher text letters with english letters based on frequency

See more:

Java

The goal is to calculate the frequency of the ciphertext letters and then replace them with English letters based on their frequency statistics.

What I have tried:

I have generated the frequencies but when I'm using the replace method it's not giving the desired output, for example, if I use one replace() method, it outputs accordingly(

String A = encryptedText.replace('a','z');

. It replaces all the 'a's with 'z's but if I add the replace methods(one replace method for each character of the alphabet for example

(<pre>  String B = encryptedText.replace('b','y');

,

(<pre>  String C = encryptedText.replace('c','x');

) and so on only the first method replace function is executed, the others are not executed and it doubles all the letters in the output, for example, if I replace 'a','b' and 'c' with 'z','y' and 'x' respectively, it outputs as "

zbcaycabxabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabc

".

Below is my code:

import java.util.Arrays;
import java.util.Scanner;

public class FrequencyAnalysisCaesarCipher {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        System.out.println("Please enter message to be decrypted: ");
        String encryptedText = input.nextLine().toLowerCase();

        int[] freq = new int[encryptedText.length()];
        int i = 0;
        int j;

        //Converts given string into character array
        char[] string = encryptedText.toCharArray();
        Arrays.sort(string);
        Arrays.sort(new int[]{freq[i]});

        for (i = 0; i < encryptedText.length(); i++) {
            freq[i] = 1 ;
            for (j = i + 1; j < encryptedText.length(); j++) {
                if (string[i] == string[j]) {
                    freq[i]++;

                    //Set string[j] to 0 to avoid printing visited character
                    string[j] = '0';

                }
            }
        }

        //Displays each character and their corresponding frequency
        System.out.println("Characters and their corresponding frequencies");
        for (i = 0; i < freq.length; i++) {
            if (string[i] != ' ' && string[i] != '0') {
                System.out.println(string[i] + "-" + freq[i]);
            }
        }
        System.out.println("..............................................");

        // oldChar is cipher text letter and newChar is English letter
        // The newChar have been initiated just so to run the program but can be replaced accordingly based on frequency and then re-run to give the desired output

        String A = encryptedText.replace('a','z');
        String B = encryptedText.replace('b','y');
        String C = encryptedText.replace('c','x');
        String D = encryptedText.replace('d','w');
        String E = encryptedText.replace('e','v');
        String F = encryptedText.replace('f','u');
        String G = encryptedText.replace('g','t');
        String H = encryptedText.replace('h','s');
        String I = encryptedText.replace('i','r');
        String J = encryptedText.replace('j','q');
        String K = encryptedText.replace('k','p');
        String L = encryptedText.replace('l','o');
        String M = encryptedText.replace('m','n');
        String N = encryptedText.replace('n','m');
        String O = encryptedText.replace('o','l');
        String P = encryptedText.replace('p','k');
        String Q = encryptedText.replace('q','j');
        String R = encryptedText.replace('r','i');
        String S = encryptedText.replace('s','h');
        String T = encryptedText.replace('t','g');
        String U = encryptedText.replace('u','f');
        String V = encryptedText.replace('v','e');
        String W = encryptedText.replace('w','d');
        String X = encryptedText.replace('x','c');
        String Y = encryptedText.replace('y','b');
        String Z = encryptedText.replace('z','a');

        System.out.print(A+B+C+D+E+F+G+H+I+J+K+L+M+N+O+P+Q+R+S+T+U+V+W+X+Y+Z);


    }
}