COMPILER Menggunakan Java

Tugas dari salah satu dosen menyuruh untuk membuat compiler dengan menggunakan bahasa pemrograman java.
COMPILER
import java.io.*;
public class Scanner
{
public static void main(String args[]) throws Exception
{
 kataInputStream kata = new kataInputStream(System.in);
 System.out.print("Masukkan Kalimat : ");
     String maskal = kata.readLine();
     char chars[] = maskal.toCharArray();
     char myChars[]={'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',+     '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',' '};     
     int numChars[]=new int[myChars.length];
     for(int x=0;x
 {
        for(int y=0;y
  {
                 if(chars[x]==myChars[y])
   {
                     numChars[y]++;
              }
         }
     }
     for (int x=0;x < myChars.length;x++)
 {
  if(numChars[x] > 0)
  {
          System.out.println(myChars[x] + " = " + numChars[x]);
  }
 }
}
}