While you are working with vncserver, you can Install it or run. If you Install it, the service would be installed and after starting the service, two processes would be appear: one is system and the other is process. If you run it, the you don't need to install the service and both process are user.
Now I've made a java program and make it service with exe4j. After installing and starting my service, two process would be appear like the vnc but both are system. Is there any way to run one another on user? Should I Change my code?
Windows services run under a system account by default. With the /install command line parameter, there is no way to specify a different user (unlike with install4j where the "Install a service" action allows you to specify a different user).
With exe4j, you would have to change the user manually in the service properties dialog.