Filip Hanik of Covalent Technologies wrote an excellent article in which he describes his series of performance/scalability tests of the new NIO connector that has been added to Tomcat 6. In tests he also includes Jetty and Glassfish containers. The article contains very good explanation of challenges in adapting NIO environment to blocking IO requirements. The good news is that the answer to the question from the title is yes, servlet containers can scale, led by Tomcat 6 that handled 16000 concurrent connections without problems.