[jetty-users] Updating Solr to allow http2

[Shawn Heisey <eclipse@xxxxxxxxxxxx>]

Solr is an Apache project that uses Jetty.

It includes a very stripped-down install of Jetty.  Recently somebody
wanted to enable HTTP/2 on their Solr server.  Presumably they're using
a client that supports it.

Solr's install of Jetty doesn't include the jars for HTTP/2.  These are
the jars we currently install in Jetty's lib directory (in our master
branch):

gmetric4j-1.0.7.jar
javax.servlet-api-3.1.0.jar
jetty-continuation-9.4.8.v20171121.jar
jetty-deploy-9.4.8.v20171121.jar
jetty-http-9.4.8.v20171121.jar
jetty-io-9.4.8.v20171121.jar
jetty-jmx-9.4.8.v20171121.jar
jetty-rewrite-9.4.8.v20171121.jar
jetty-security-9.4.8.v20171121.jar
jetty-server-9.4.8.v20171121.jar
jetty-servlet-9.4.8.v20171121.jar
jetty-servlets-9.4.8.v20171121.jar
jetty-util-9.4.8.v20171121.jar
jetty-webapp-9.4.8.v20171121.jar
jetty-xml-9.4.8.v20171121.jar
metrics-core-3.2.2.jar
metrics-ganglia-3.2.2.jar
metrics-graphite-3.2.2.jar
metrics-jetty9-3.2.2.jar
metrics-jvm-3.2.2.jar

So to make this possible, I need to add the three jars that are in
lib/http2 ... but from what I can tell, I also need to add
jetty-alpn-server.

The Solr codebase uses ivy for dependency management.  The dependencies
showing on Maven Central for the http2 jars and jetty-alpn-server don't
show any other dependencies that Solr is missing, but if I look at the
Jetty 9.4.8 download, I do see some other jars that look possibly
related -- like alpn-api, and a number of other jetty-alpn jars.

Is Maven showing the correct dependency information, or do I need these
other alpn jars in order to enable HTTP/2?  Is there anything else that
I need that I haven't touched on?

Thanks,
Shawn