Help: Substitution cipher

Question

Hi:
The following program is to suppose to be an alphabet substitution cipher. A keyword is taken from the command and added to a reverse alphabet string. Duplicate letters are removed. The string is then put into an array. The array is then used to encrypt incoming text by substituting characters based on position.
The methods I have developed seem to work. The problem I am having is the actual substitution of characters. I keep getting the error message java.lang.ArrayIndexOutOfBoundsException. Please give input on how I could correct this problem and make the program work.
Thanks.
C:\jdk1.2.2\bin>java Monoalphabet feather in.txt out4.txt
Exception: java.lang.ArrayIndexOutOfBoundsExceptionimport java.io.*;
class Monoalphabet {
  public static void main(String args[]) {
    String keyword = args[0];
    try {
     int positionOfA = 'a';
     String incoming = "";
     String temp = "";
     String outgoing = "";
     // Create a file reader
     FileReader f = new FileReader(args[1]);
     BufferedReader infile  = new BufferedReader(f); 
     // Create a file writer
     FileWriter f1 = new FileWriter(args[2]);
      while((temp = infile.readLine()) != null)
          for (int k = 0; k < temp.length(); k++)
          char whatever = temp.charAt(k);
          char [] c = makeCypher(keyword);
          char ch = c [(int)whatever -  positionOfA];//causes an error
          String chs = new Character (ch).toString();
       outgoing = outgoing + chs;
         f1.write(outgoing);
      // Close the file writer
      f1.close();
      // Close file reader
      f.close();
    catch(Exception e) {
      System.out.println("Exception: " + e);
  public static String removeDups(String keyword)
  { String remove = "";
    keyword = keyword + "zyxwvutsrqponmlkjihgfedcba";
   for(int i = keyword.length()-1; i > -1 ; i--)
   if(i == keyword.indexOf(keyword.charAt(i)))
    remove = keyword.charAt(i)+ remove;
    return remove; 
  public static  char[] makeCypher(String keyword)
      int len = keyword.length();// putting the characters in an array
      char Array[] = new char[ len ];
      for (int i =0;i < keyword.length();i++)
     { Array = keyword.charAt(i);
return Array;// Is this the correct?

Answer 1

What is the size of your array, and what is the index being used in the array which causes this to fail? This is standard debugging work that you should be doing when you get this type of error.