Execute gradle tasks:

• generate keystore

$ ./gradlew genkey

or manually:

$ keytool -genkey -alias calc -keyalg RSA -keystore calc.jks -keysize 2048
$ cp calc.jks ~/.keystore

• generate certificate

$ keytool -export -alias calc -keystore calc.jks -rfc -file calc.csr

Important: Add the certificate as a trusted one in Java Control Panel. For Mac: System Preferences > Java > Open Java Control Panel > Security tab > Manage certificates > User > Import. Import it possibly everywhere (trusted certificates, secure site etc.).

• create *.jnlp file with a signed jar

$ ./gradlew createWebstart

It will create webstart files at build/jnlp.

Copy the contents of build/jnlp to Tomcat's webapps/ROOT folder.

Go to Tomcat's bin folder and execute startup script.

$ cd /opt/apache-tomcat-9.0.8/bin
$ ./startup.sh

Note: check if Tomcat is running with ps -ef | grep tomcat and eventually kill the kitten: pkill -9 -f tomcat.

Shorten: ./killtomacat.sh

In web browser:

http://localhost:8080/launch.jnlp

It will download the jnlp file. Execute it and enjoy the calculator.

Commands I found useful:

Sign jar manually:

jarsigner -keystore ../../../calc.jks -storepass hania123 -keypass hania123 lab8__V1.0-SNAPSHOT-calc.jar calc

Unpack *.pack.gz file for whatever reason:

unpack200 *.jar.pack.gz *.jar