I have an application consisting of three web applications running on JBoss 1.4.2 on a Linux Redhat server. I'm using Solr/Lucene to create and maintain a frequently updated index. Once updated, the index is copied to another directory used for searching. Old index-files in the search directory are then deleted. The streams used to copy the files are closed in finally-blocks. After a few days an IOException occurs because of "too many open files". When I run the linux command

ls -l /proc/26788/fd/

where 26788 is jboss' process id, it gives me a seemingly ever-increasing list of deleted files, marked with 'deleted' in parantheses. They are all located in the search directory. From what I understand this means that something still holds a reference to the file, and that the file will be permanently deleted once this something loses its reference to it.

Only SolrIndexSearcher objects are in direct contact with these files in the search application. The searchers are local objects in search-methods, and are closed after every search operation. In theory, the garbage collector should collect these objects later (though while profiling other applications I've noticed that it often doesn't garbage collect until the allocated memory starts running out).

The other objects in contact with the files are the FileOutputStreams used to copy them, but as stated above, these are closed in finally-blocks and thus should hold no reference to the files.

I need to get rid of the "too many open files"-problem. I suspect that it is related to the almost-deleted files in the proc-dir, but I know too little of Linux to be sure. Does the problem ring a bell to anyone, or do you have any ideas as to how I can get rid of the problem?

All help is greatly appreciated.