Caesar Cipher in Java

cipher.java

import java.io.*;
import java.util.ArrayList;
import java.util.Iterator;

public class cipher
{
    public static void main(String[]args)
    throws java.io.IOException
    {
        FileReader     ReadFile = new FileReader("input.txt");
        BufferedReader ReadFileBuffer = new BufferedReader(ReadFile);

        FileWriter     WriteFile = new FileWriter("output.txt");
        BufferedWriter WriteFileBuffer = new BufferedWriter(WriteFile);

        ArrayList<String> inputArray = new ArrayList<String>();
        String            currentLine;
        int               lineCounter = 0;

        while((currentLine = ReadFileBuffer.readLine()) != null)
        {
            inputArray.add(currentLine);
            lineCounter++;
        }
        ReadFileBuffer.close();

        Iterator<String> iter = inputArray.iterator();
        while(iter.hasNext())
        {
            String line = iter.next().toUpperCase();
            for(int i=0;i<line.length();i++)
                WriteFileBuffer.write(cipherLetter(line.charAt(i), true));
            WriteFileBuffer.write("\n");
        }
        WriteFileBuffer.close();
    }

    public static char cipherLetter(char letter, boolean encode)
    {
        int cipherLength = 3;
        int ascii = (int)letter;

        if (ascii>=65 && ascii<=90)
        {
            ascii += encode ? cipherLength : -cipherLength;
            ascii = (ascii-65);
            if (ascii < 0 ) ascii += 25;
            ascii = ascii % 25 + 65;
        }
        return (char)ascii;
    }
}