A Distributed Java Virtual Machine (DJVM) is a cluster-wide set of extended JVMs that enables parallel execution of a multithreaded Java application. It has proven effectiveness for scaling scientific applications. However, leveraging DJVMs to cluster real-life web applications with commercial server workloads has not been well studied. This paper presents a new generic clustering approach based on DJVMs that promote user transparency and global object sharing for web application servers. We port Apache Tomcat to our JESSICA2 DJVM and study the performance of a wide range of web applications running on the server. Our experimental results show that this approach can scale better than the traditional clustering approach, particularly for cache-centric web applications.