When you say “is there an easier way to… trust this cert”, that’s exactly what you’re doing by adding the cert to your Java trust store. And this is very, very easy to do, and there’s nothing you need to do within your client app to get that trust store recognized or utilized.
On your client machine, find where your cacerts file is (that’s your default Java trust store, and is, by default, located at <java-home>/lib/security/certs/cacerts.
Then, type the following:
keytool -import -alias <Name for the cert> -file <the .cer file> -keystore <path to cacerts>
That will import the cert into your trust store, and after this, your client app will be able to connect to your Grizzly HTTPS server without issue.
If you don’t want to import the cert into your default trust store — i.e., you just want it to be available to this one client app, but not to anything else you run on your JVM on that machine — then you can create a new trust store just for your app. Instead of passing keytool the path to the existing, default cacerts file, pass keytool the path to your new trust store file:
keytool -import -alias <Name for the cert> -file <the .cer file> -keystore <path to new trust store>
You’ll be asked to set and verify a new password for the trust store file. Then, when you start your client app, start it with the following parameters:
java -Djavax.net.ssl.trustStore=<path to new trust store> -Djavax.net.ssl.trustStorePassword=<trust store password>
Easy cheesy, really.