JODConverter needs to connect to a running instance in order to perform the document conversions.

This is different from starting the program as you would normally do. can be configured to run as a service and listen for commands on a TCP port; there are a few ways to accomplish this but the simplest one is to start it from the command line with the following options:

  soffice -headless -accept="socket,host=,port=8100;urp;" -nofirststartwizard

See the Uno/FAQ on the Wiki for more on this topic.

The service must be running for JODConverter to work at all. You can think of the service as something similar to a database server here: many applications require a database; if the database server is not running the application will not work. JODConverter needs to connect to an service; if it is not running… you get the idea. Unless otherwise configured, JODConverter assumes that is running on port 8100.

Using an Service on a different machine

Although it is possible to run and connect to an on a different machine, this approach is now discouraged by the author of JODConverter because it leads to various problems. See the above-mentioned Wiki page if you insist in adopting this solution.

The suggested approach instead is to run JODConverter as a web service on the same machine where is installed, and then use the web service from other machines as required.