Error in running file

Question

I write a program to convert a plain message into a scrambled message. During the compliation, nothing happened. When I run the program, it says ArrayIndexOutOfBondsException: 26. I have no idea how to solve the problem. I have highlighted the line which caused the error.
Pls guide.
import java.io.*;
import javax.swing.*;
public class Q2
public static void main (String[] args)
//first section
boolean found = false;
String abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char ch[ ] = new char[26];
ch[0] = 'C';
ch[1] = 'A';
ch[2] = 'R';
ch[3] = 'E';
int next = 4;
for (int i = 0; i < 26; i++)
found = true;
for ( int j = 0; j < 4; j++)
if (abc.charAt(i) == ch[j])
{     found = true;
break;
ch[next] = abc.charAt(i); //the line which caused the error.
next++;
System.out.println("Scrambled: " +ch);
String plain = JOptionPane.showInputDialog("Enter message");
String coded= "\n: coded ";
for ( int word = 0; word < plain.length(); word ++)
char c = plain.charAt(word);
int counter = 0;
while ( c == abc.charAt(counter))
counter++;
c = ch[counter];
counter = 0;
System.out.println(+c);
}

Answer 1

My intention is to create a secret row where any message entered will be scrambled according to the secret row.
String abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; //plain row
                          ch = CAREBDFGHIJKLMNOPQSTUVWXYZ    // secret rowso the purpose of the code below is to create the secret row shown above.
boolean found = false;
          String abc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
          char ch[] = new char[26];
          //abc = ch;
          ch[0] = 'C';
          ch[1] = 'A';
          ch[2] = 'R';
          ch[3] = 'E';
          int next = 4;
          for (int i = 0; i < 26; i++)
          //   found = true;
              for ( int j = 0; j < 4; j++)
                 if (abc.charAt(i) == ch)
found = true;
break;
if(next < 26)
ch[next] = abc.charAt(i);
next++;
System.out.println("Scrambled: " +ch);