Open Java Control Panel and select tab Advanced and enable "Enable tracing", "Enable logging" and "Show applet lifecycle exception". Apply and close web broser and open RIA, Rich Internet Applicatio, i.e. Applet or Java Web Start Application.
Your log file will be stored under $USER_HOME + File.separator + log + File.separator, on Windows that is C:\Users\your-username\AppData\LocalLow\Sun\Java\Deployment\log
To add more trace add the following to $USER_HOME + File.separator + deployment.properties, on Windows that is C:\Users\your-username\AppData\LocalLow\Sun\Java\Deployment\deployment.properties
deployment.javaws.jre.0.args=-Djava.security.debug=all -Djavax.net.debug=all
deployment.javaws.jre.1.args=-Djava.security.debug=all -Djavax.net.debug=all
Reference:
-Djava.security.debug
-Djavax.net.debug