The JAXFront HTML renderer runs initially with the free community license.
If you have received a license file, replace the community license with your own license file. Locate the installation directory of your WebApplication server (i.e. Tomcat) and navigate to the "webapps" folder. Go to the directory "jaxfront/lic" and replace the file "jaxfront-community.lic" with your own license file. Be sure you delete the community license.
If you are using JavaSwing see here.