When tuning Oracle jServ you can encounter the security.maxConnections directive in the jserv.properties settings file. security.maxConnections, indeed, sets the max number of connections that jServ can concurrently handle. It can be very tempting to set this to a very high level, this is however not a good idea. First, you have to consider if your server would be able to handle the load of a high number of concurrent connections. Secondly the effect of this setting is related to the number of file descriptors your operating system can handle.
A file descriptor is a handle created by a process when a file is opened. There is a limit to the amount of file descriptors per process. On how to set / reset the max number of file handlers is something I already described in my post file-max and semmni parameters. So when trying to upgrade the max number of connections your system can handle this is something to remember and check before you tune the settings in your jserv.properties file.