tokenizing a java file

Hi i am new to java and i am trying to build lexecal analyser for java code , I am in the beginning want to read the file then tokanize it, so i wrote this code that read line from the buufer , put it in string then put the tokens into array of string ,but after run the code it gives" error:null" plz kindly could any of you tell me what is wrong in it . also i want to use the tokenizer class but i don't know how to use it,realy i would be thankful if you kindly help me in this . print("import java.io.*; import java.util.Scanner;

class FileRead{

@SuppressWarnings("null") public static void main(String args[]) {

  try{

FileInputStream fstream = new FileInputStream("always.java");
new BufferedReader(new InputStreamReader(fstream));

    BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
String strLine = " ";
String tokens[] = null ;
int i=0;
//Read File Line By Line

Scanner input = new Scanner( strLine );
while ( (strLine =br.readLine()) != null)   {
    //StringTokenizer st =new StringTokenizer(fstream);
    //System.out.println (strLine);

while(( tokens[i]=input.next())!= null){

  System.out.println (tokens[i]);
     i++;

}}

//Close the input stream

// in.close(); }catch (Exception e){//Catch exception if any System.err.println("Error: " + e.getMessage());

} }}

");

May 30, 2011 at 12:55 PM

import java.io.*;
import java.util.*;

class FileRead{

 public static void main(String args[]) {

  try{

File f=new File("FileRead.java");
BufferedReader br = new BufferedReader(new FileReader(f));
String strLine = " ";
String filedata="";
while ( (strLine =br.readLine()) != null)   {
filedata+=strLine+" ";
}
StringTokenizer stk=new StringTokenizer(filedata);
   while(stk.hasMoreTokens()){
       String token=stk.nextToken();
       System.out.println(token);
   }
br.close(); 
 }catch (Exception e){
     System.err.println("Error: " + e.getMessage());

}
}
}