If jEdit is started while another copy is already running, control is transferred to the running copy, and a second instance is not loaded. This saves time and memory if jEdit is started multiple times. Communication between instances of jEdit is implemented using TCP/IP sockets; the initial instance is known as the server, and subsequent invocations are clients.

If you find yourself launching and exiting jEdit a lot, the startup time can get a bit bothersome. If the -background command line switch is specified, jEdit will continue running and waiting for client requests even after all editor windows are closed. When run in background mode, you can open and close jEdit any number of times, only having to wait for it to start the first time. The downside of this is increased memory usage.

Thanks for quick tips.