Which exact version of JBoss AS7 is this? How many war files are you deploying?
please provide info that jaikiran asked, you can also can you check what are the open files, from where do they come from?
you can do that by running
problem might be just releated to actually using lots of open file handels (note that linux also threats open socket connections as file handles)
in that case solution for you would be to increase the limit of maximum open files as default is quite low (1024).
for more info on how to do that read: http://www.cyberciti.biz/faq/linux-increase-the-maximum-number-of-open-files/ and http://stackoverflow.com/questions/34588/how-do-i-change-the-number-of-open-files-limit-in-linux
But it is actualy possible that there is some file handle leak in some code somewhere, that is why i would recomend first to try to debug why there are so many open handles and what are they.