I need to run two webapps on a ubuntu VPS but one(my own webapp) prefers to run in Tomcat & other(Solr webservice) is preferable in Jetty. But I think running a separate server for each webapp would be consuming more resources (like memory consumption would be higher) than both the webapps running on same server, isn't it ?
What may be the other bad if I run both Tomcat & Jetty on a single machine for production use?
A couple of things I can think of, some of which you've mentioned:
more resources are consumed (memory usage of two containers running is generally going to be more than one container running). Also, there could be implications for things like database connections and caching if you have two containers instead of one.
containers have to run on different ports (but there are ways to make it appear to the site visitor that they're on the same port)
Having said that, I run tomcat and jetty side by side all the time on my dev machine and things work just fine. But development, not performance, is my major goal when running on my dev machine.
Running Tomcat and Jetty in the same machine is something that "performance wise" is not so "heavy", I have both running (almost) all the time in my dev machine... in production I am using only Tomcat (running multiple web services in the same container - mainly my web services + Solr) and I do not experience major differences on performance in both scenarios. So I would say that it depends on your needs... personally I tend to prefer to simplify my production setup and avoid having multiple containers in multiple ports on my servers. Furthermore, Tomcat does seem to be more popular solution for java container (http://zeroturnaround.com/rebellabs/the-great-java-application-server-debate-with-tomcat-jboss-glassfish-jetty-and-liberty-profile/), this does not however mean it is the best one for all scenarios. I personally tend to stick with one Tomcat in production...
Yes, it does consume more resources to run two instead of one, but for development purposes it shouldn't be a problem as long as your personal computer isn't terribly under powered. Other than that, you will have to resolve any port conflicts that come up when you start the second process. The error messages should tell you what port is conflicted and all port numbers are configurable.
