Encoding A Message Using Caesar Shift

I have an assignment, similar to ones of seen in the past. The assignment is to take a users text input and to encrypt it using 3 different types of encryptions: Caesar, Transpose, and Reverser. The professor gave us the bulk of the code, and more specifically how to tokenize and shift the letters using Caeser shift. The problem im coming across is that it is not showing anything past the users input. After running it, it just stays there running without showing anything.

Cipher:

package cipher;
import java.util.Scanner;
import java.util.StringTokenizer;
import javax.swing.JOptionPane;
public abstract class Cipher {
public String message;
StringBuilder encrypted_message, decrypted_message;

[Code] ....

The constants have their own separate class, and they appear to work fine. I know that the Transpose and Reverser are incomplete, hence them commented out. But if i cant finish with Caeser first, it wont work at all.