I hope this doesn't sound rude, but you don't sound like you have the experience necessary to be designing security systems. These are complicated systems that require both extensive domain knowledge and strong coding skills. To answer your question, though, these systems tend to require very tight integration with the operating system and the network than Java provides. It probably isn't the best choice for a language/platform to develop your system on.
Originally posted by sai kamesh chirala: i would like to do a project like designing a firewall or network intruder system in java. is it posssible if so please guide providing a over view
I assume that your interest is to work on a "learning project" to learn security concepts and also that you are comfortable with Java. Reading your question, I also get a feeling that you probably want to learn more on firewalls and intrusion detection systems. Look at iptables, an opensource firewall implementation for Linux and Snort, an opensource intrusion detection system. This should give a good feel about what these systems are. Now, if you want to learn more about firewalls and/or intrusion detection systems then you should just play with these systems and if extend them (if you can). However, if you want to learn more about Java security then I will recommend a visit to my book's website. If you want some specific project ideas around Java Security then let me know and I may be able to offer some guidance. [ November 21, 2003: Message edited by: Pankaj Kr ]