I would like to suggest a simple alternative based on certificate ripper which I have built myself. It extracts the server certificate and adds it the cacert truststore of the jdk. See below for the command.
crip export jks -u=https://[HOST:[PORT] -d=$JAVA_HOME/jre/lib/security/cacertsIn some cases you need to run it with sudo or admin rights. It is available for Windows, Mac and Linux. Binaries can be found here: certificate ripper binaries