polyalphabetic cipher java code

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.DocumentFilter;

 
public class PolyTransMain{
    
    /** Creates a new instance of DesMain */
    public PolyTransMain() {
    }
    
    public static void main(String [] rr){
        DesPanel  mm = new DesPanel();
        mm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mm.setVisible(true);
    }
}
class DesPanel extends JFrame{
    public DesPanel(){
        this.setTitle("PolyTrans");
        this.setSize(800,800);
        this.setVisible(true);
        
        GenerateGUI();
    }
    PolyTrans p;
    public static   JTextArea StepsText = new JTextArea(10,40);
    
    
    private    Container c=this.getContentPane();
    private    JButton btnCihper = new JButton("Cipher");
    private    JButton btnDeCihper = new JButton("Decipher");
    
    private   JTextArea CipherText = new JTextArea(4,40);
    private   JTextArea OriginalText = new JTextArea(4,40);
    private   JTextArea DeCipherText = new JTextArea(4,40);
    
    
    private    JScrollPane OriginalScorl=new JScrollPane(OriginalText,
            JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    private    JScrollPane CipherScorl=new JScrollPane(CipherText,
            JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    private  JScrollPane DecipherScorl=new JScrollPane(DeCipherText,
            JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    private   JScrollPane StepScorl=new JScrollPane(StepsText,
            JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    private  JTextField KeyWord = new JTextField(16);
    private  JTextField KeyWordTwo = new JTextField(16);
    private  JPanel PanelCipher = new JPanel();
    private  JPanel PanelDecipher = new JPanel();
    private  JPanel PanelKeyWord = new JPanel();
    
    private  JPanel PanelOriginaltxt = new JPanel();
    private JPanel jpstep=new JPanel();
    
    private  JLabel lblKeyWord= new JLabel("KeyWord : ");
    
    
    private void GenerateGUI(){
        c.setLayout(new GridLayout(4,1));
        
        c.setLayout(new FlowLayout());
        
        PanelKeyWord.setLayout(new FlowLayout());
        PanelKeyWord.add(lblKeyWord);
        PanelKeyWord.add(KeyWord);
        
        
        PanelOriginaltxt.setBorder(BorderFactory.createTitledBorder("Original Text"));
        PanelOriginaltxt.setLayout(new FlowLayout());
        PanelOriginaltxt.add(OriginalScorl);
        
        PanelCipher.setBorder(BorderFactory.createTitledBorder("Cipher Text"));
        PanelCipher.setLayout(new FlowLayout());
        PanelCipher.add(CipherScorl);
        PanelCipher.add(btnCihper);
        
        PanelDecipher.setBorder(BorderFactory.createTitledBorder("Decipher Text"));
        PanelDecipher.setLayout(new FlowLayout());
        PanelDecipher.add(DecipherScorl);
        PanelDecipher.add(btnDeCihper);
        jpstep.setBorder(BorderFactory.createTitledBorder("Mointor"));
        jpstep.setLayout(new FlowLayout());
        jpstep.add(StepScorl);
        
        
        c.add(PanelKeyWord);
        
        c.add(PanelOriginaltxt);
        c.add(PanelCipher);
        c.add(PanelDecipher);
        c.add(jpstep);
        
        DoActions();
        
        
    }
    private void DoActions(){
        ActionHandler action = new ActionHandler();
        
        btnCihper.addActionListener(action);
        btnDeCihper.addActionListener(action);
        
    }
    
    private class ActionHandler implements ActionListener{
        
        
        public void actionPerformed(ActionEvent e) {
            if(e.getSource()==btnCihper){
                String plaintext=OriginalText.getText();
                String keyworD=KeyWord.getText();
                StepsText.append("keyword : "+keyworD+'\n');
                StepsText.append("PlainText : "+plaintext+'\n');
                p= new PolyTrans(keyworD,plaintext);
                p.Encrypt();
                p.FillCharacMatrix();
                
                
                CipherText.append(p.getCipher());
                
            }
            if(e.getSource()==btnDeCihper){
                p.Decrypt();
                
                
                DeCipherText.append("\n"+p.getDeCipher());
            }
        }
        
    }
    private String fina;
    
}

class DocumentSizeFilter extends DocumentFilter {
    int maxCharacters;
    
    public DocumentSizeFilter(int maxChars) {
        maxCharacters = maxChars;
    }
    
    public void insertString(FilterBypass fb, int offs, String str, AttributeSet a) 

throws BadLocationException {
        
        if ((fb.getDocument().getLength() + str.length()) <= maxCharacters)
            super.insertString(fb, offs, str, a);
        else
            Toolkit.getDefaultToolkit().beep();
    }
    
    public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a) 

throws BadLocationException {
        
        if ((fb.getDocument().getLength() + str.length()- length) <= maxCharacters)
            super.replace(fb, offs, length, str, a);
        else
            Toolkit.getDefaultToolkit().beep();
    }
    
}

import java.util.Scanner;

public class PolyTrans {
    
    /** Creates a new instance of PolyTrans */
    public PolyTrans(String key, String plain) {
        keyword=key;
        PlainText=plain;
    }
    
    public void UserEntery() {
        
        
        
        
        
        
        Encrypt();
        FillCharacMatrix();
        Decrypt();
        
    }
    
    public String getCipher(){
        return cyphir;
    }
    
    
    public String getDeCipher(){
        return dcyphir;
    }
    
    
    public void FillCharacMatrix(){
        
        for(int i=0; i<=25; i++){
            for(int j=0; j<=25; j++){
                CharMatrix[i][j]=characters[(j+i)%26];
            }
        }
        
        for(int i=0;i<=25;i++) {
            
            System.out.print(" | ");
            for(int j=0;j<=25;j++) {
                
                
                System.out.print(" "+CharMatrix[i][j]+" ");
            }
            System.out.println(" | ");
            
        }
    }
    
    public void Encrypt() {
        int sub1=0,sub2=0,sub3=0;
        int sub=0;
        char char_num;
        int start=0;
        for(int i=0; i<PlainText.length(); i++) {
            sub1=PlainText.substring(i,i+1).codePointAt(0);
            sub2=keyword.substring(start,start+1).codePointAt(0);
            start++;
            sub3=sub1+sub2;
            sub3=sub3%97;
            sub=sub3%26;
            
            if(cyphir==null)
                cyphir=""+characters[sub];
            else
                cyphir+=characters[sub];
            
            
            
            if(start==keyword.length()){
                start=0;
            }
            
            
        }
        System.out.println("The Cipher Text is: "+ cyphir);
    }
    public void Decrypt(){
        int sub1=0,sub2=0,sub3=0;
        int keyword_len;
        int sub=0;
        int cyphir_len;
        char char_num;
        int start=0;
        for(int i=0; i<PlainText.length(); i++) {
            sub1=cyphir.substring(i,i+1).codePointAt(0);
            sub2=keyword.substring(start,start+1).codePointAt(0);
            
            start++;
            
            sub1=(sub1%97)%26;
            sub2=(sub2%97)%26;
            
            
            for(int k=0; k<26; k++) {
                sub3=(Integer.parseInt(""+(short)CharMatrix[sub2][k])%97)%26;
                
                if(sub1==sub3){
                    
                    if(dcyphir==null)
                        dcyphir=Character.toString(CharMatrix[0][k]);
                    else
                        dcyphir+=Character.toString(CharMatrix[0][k]);
                }
            }
            
            
            
            
            
            
            if(start==keyword.length()){
                start=0;
            }
            
            
        }
        System.out.println("The Dciphir Text is: "+ dcyphir);
        
    }
    
    
    private  int Len=0;
    private String keyword;
    private String PlainText;
    private String cyphir;
    private String [][] charmatriex;
    private String matrixv;
    private char [][] CharMatrix=new char[26][26];
    private char characters[]= {'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'};
    private String dcyphir;
    
}