Short version
How can I determine the Java version a remote server is running if I only have access to the server through port 443?
Long version
I am validating a pentest run by another group. They found an error message that provided the Java version being run by the remote server. The Java version was an old one. The developers have apparently made changes that prevent the error message from appearing, thus hiding the Java version.
My job is find out if the developers also updated the java version. How can I do that without access to the server other than through HTTPS via port 443?