This is an issue with the default server.xml file. I hope I chose the correct Component The org.apache.catalina.Cluster interface defines methods named "setClusterName" and "getClusterName", implying a property named "clusterName". However, the server.xml for every version of Tomcat that I've looked at (5.0.18, 5.0.29, 5.5.9, 5.5.12-alpha) indicates a <Cluster> attribute called "name". The earlier 5.0 releases even include 'name="FilipsCluster"' in the commented-out sample <Cluster> config. The problem is that the server.xml should not indicate an attribute called "name" for the <Cluster> element, rather the same attribute should be called "clusterName". Indeed, setting the <Cluster> attribute "name" (and not "clusterName") causes "getClusterName" to return null - but setting a <Cluster> attribute called "clusterName" returns the specified value in a call to "getClusterName". The fix is trivial - replace the name of the <Cluster> attribute "name" with "clusterName" throughout the server.xml file (2 places in early 5.0 server.xml files, only 1 place in later builds). This is an easy thing for users to do, but finding the problem in the first place is the tricky part.
Corrected attribute name documentation in conf/server.xml. Thanks for pointing this out.