This package provides the development files of the jsvc application. For a description please have a look at the packages jsvc and libcommons-daemon-java.
libcommons-daemon-java | library to launch Java applications as daemons | Mehr ...
The Daemon package from Jakarta Commons can be used to implement Java applications which can be launched as daemons. For example the program will be notified about a shutdown so that it can perform cleanup tasks before its process of execution is destroyed by the operation system. . This package contains the java library. You will also need the actual binary for your architecture which is provided by the jsvc package.