Input and output in Java

Sorry look that problem I am having I have created the necessary command but it is giving me a null pinter.
Here is the file



/**
 *  Written by: GFlexz
 *  Date      : 23-02-2003
 *  Purpose   : Accept file names and compare
 *              name if not a directory and writer to and fro
 *              of the file name.
 */
 
 import java.net.*;
 import java.io.*;
 
public class InputOutput extends Object{
    public static void main (String[] args){
                               
        String first;
        String second;
        BufferedWriter  write = null;
        BufferedReader  read  = null;
        BufferedReader in = new BufferedReader ( new InputStreamReader ( System.in ));
       
       
       
        try{
            System.out.println( "Enter the first file name:  " );
            first = in.readLine().trim();
            System.out.println ( "Enter the second file name" );
            second = in.readLine().trim();
       
     
            File firstFile  = new File ( first  );
            File secondFile = new File ( second );
           
            if ( firstFile.isDirectory ( ) != true ){
                write = new BufferedWriter ( new FileWriter ( secondFile ) );
            }//End if
           
            if ( secondFile.isFile      ( ) != true ){
                read  = new BufferedReader ( new FileReader ( firstFile  ) );
            }//End if
            int Q;
            while(  (Q = read.read())  != -1 ){
                write.write ( Q );
             }
           
            write.close();
            read.close();

            }catch ( java.lang.SecurityException e ){
                System.out.println( e.getMessage ( ) );
           }catch ( java.io.IOException e ){
                System.out.println( e.getMessage() );
           }//End try

    } // main method
} //UniCodeConverter class

As you need to manipulate the file at the byte level, you should read using a stream, and not a reader.

> if ( secondFile.isFile      ( ) != true ){

This checks if the secondFile is not a file, not if it doesn't exist.

Instead try:

if (!secondFile.exists( )){

On which line do you get the NullPointerException?

On this line
while(  (Q = read.read())  != -1 ){

And I am trying to write a loop that goes through a number and compare the next number i.e

if
int name[] = {2,12,19,30,12}
int name[1] = 12; is immediately followed by name[2] = 19

Or even better;

if ( firstFile.exists() && firstFile.isFile() && !secondFile.exists()){
      write = new FileOutputStream( secondFile ));
      read  = new FileInputStream( firstFile  ) );

      // perform copy

      write.close();
      read.close();
}

Vfwood

Thanks for your answer that is what I was looking for.  Before I award you the point which you deserve please can you tell me how to change the value 111 is immediately followed by the value 101, they should be replaced by the single value 248.

Thanks
GFlexz

vfwood,

Please be aware that doing peoples homework is not permitted on this site.

No one is doing my homework for me wfwood. I am only getting some concepts of my actual program.  All the questions I ask here is design by me and variably it is not my homework but rather a very small idea in doing my project.  If you have a problem with that then It is a pity.  My project is to design and deploy simulations distributed system.  If you think any of my question is regarding my assignment. Contact www.sbu.ac.uk and follow the link(s) to academic misconduct code.  I am sure there will be very interested hearing from you.  Yes remind them that one student doing his thesis on distributed system is getting help from objects & wfwood.

Thanks
GFlexz

Can someone else please help in how to change the value 111 is immediately followed by the value 101.

GFlexz:
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