This is due to the mixed code security which needs to be set to : “Enable – hide warning and run with protections”

To deploy this setting to all computers on a network via Group Policy follow the guide below , here is the Java Reference

Create a GP to delpoy the following file to C:\Windows\Sun\Java\Deployment\deployment.config

deployment.system.config.mandatory=true
deployment.system.config=file:///C:/WINDOWS/Sun/Java/Deployment/deployment.properties

Create a GP to delpoy the following file to C:\Windows\Sun\Java\Deployment\deployment.properties

# Mixed code (sandbox vs. trusted) security verification
deployment.security.mixcode=HIDE_RUN