At my current job, we make GIS websites, using rails and geoserver. I develop on mac, and for some clients we need to deploy on windows. One client is still using an Oracle database, while in general I prefer to work with postgis databases, and also geoserver offers better support when using postgis.

So: when working locally I got a really weird phenomenon in my geoserver: it duplicated various oracle columns. Generally, for viewing not a problem but when using WFS I got the “column ambigously defined”, and using Oracle SQL Views did not work (it went looking for meta data?) and the Geoserver SQL Views were painfully slow.

But on my clients server I installed Geoserver 2.6.3 and the oracle stuff just worked. Woot :) So I had to upgrade my ancient 2.3.3 geoserver. It is running inside a tomcat. Upgrading seemed easy enough: copy the old geoserver folder somewhere (actually you would only need the data folder and the web.xml but I am lazy/extra safe like that), and drop the new war, and theoretically, we should be good to go.

Except … I got this peculiar error in my log-file

SEVERE: Error listenerStart

WTF! Thanks to some googling, I added a file to my geoserver\WEB-INF\classes with the following content:

org.apache.catalina.core.ContainerBase.[Catalina].level = DEBUG
org.apache.catalina.core.ContainerBase.[Catalina].handlers = java.util.logging.ConsoleHandler

restarted my tomcat, and the following appeared:

SEVERE: Error configuring application listener of class org.geoserver.platform.GeoServerHttpSessionListenerProxy
java.lang.UnsupportedClassVersionError: org/geoserver/platform/GeoServerHttpSessionListenerProxy : Unsupported major.minor version 51.0 (unable to load class org.geoserver.platform.GeoServerHttpSessionListenerProxy)

Now what the hell cryptic error is that? But apparently this is a very compact way to say this code needs java 1.7 and I am still using java 1.6 (I am looking at you Apple). Updating now :)