Java and Client/Server

So you think client-server programming is only for large applications?
Java and Security

Java has some strict security restrictions. An applet can only open a socket to the server on which it was loaded. Applications, on the other hand, are allowed to open sockets to any machine. My client is written as a stand-alone application for this reason. (I don't have access to a web server that will allow me to run my CB server.) There are very few major differences between an applet and an application. An applet extends the class applet and an application extends the class frame. Refer to a book on Java for more specific details.

Conclusion

This project was my first real attempt at client-server programming. I'm hooked! With the basic server written, it is possible to extend the code to do many things. I would like to eventually redesign the user interface to make it look better and be easier to use. Having Linux at home has made the program development process much easier. I was able to use the same tools on both my home system and the Sun workstations at school so a simple recompilation was all that was necessary for the server to run on a Sparc 5. My hope is that someone else will find this work useful. No references could be found in any Java book (I have three) to address this specific application. While client-server applications were available in all of these books, all of the servers were written in Java. Java works well for writing servers, but is not as fast and requires more system resources to run. Every language has its place and Java is no exception. Java is very useful as a client programming language; it's here to stay.

Take a look at the listings:

References
  • Java in a Nutshell

  • David Flanagan (1996, O'Reilly & Associates, Inc)

  • Java Programming Explorer

  • Neil Bartlett, Alex Leslie, and Steve Simkin (1996, Coriolis Group Books)

  • Teach Yourself Java in 21 Days

  • Lemay and Perkins (1996 Sams.net publishing)

  • Internetworking with TCP/IP vol III

  • Comer and Stevens (1993, Prentice-Hall, Inc)

  • The C Programming Language, second edition

  • Kernighan and Ritchie (1988, 1978, Prentice Hall)

  • Various Linux man pages

Joe Novosel (jnovosel@cc.gatech.edu) has been an avid computer hobbyist since 1981, when his first computer (Radio Shack Color Computer) had a whopping 4K of memory (including video memory!). He has been using Linux for about two years—since version 1.1.47—and thinks Linux brings back the excitement of his early days in computing. After several years in the electrical trade, Joe decided to return to school and is now a Junior at Georgia Tech, where he pursues a degree in Computer Science.

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C does have threads

ansa256's picture

C does not have threads? I think it does, I've been working with threads in C for quite a long time, POSIX threads especifically (-lpthread flag for gcc).

Threads

Mitch Frazier's picture

Bad info in this article, of course C has threads. What C doesn't have is "built-in" support for threads and concurrency. Java on the other hand does provide language level constructs for such things.

Mitch Frazier is an Associate Editor for Linux Journal.

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