I am aware of how to secure a connection: http://sparkjava.com/documentation.html#secure
But this does not enable client certificate-based authentication (I am trying to implement Estonian identity card user authentication)
After research I found a link where it is said that it cannot be done in Spark: https://groups.google.com/forum/#!topic/sparkjava/dnCKl-W018A
Fortunately it is an old post.
How do to this with SparkJava embedded Jetty container?