In my Google App Engine project, I’m currently using Twig for accessing the Datastore (but I suspect my question would be relevant for other 3rd party libs like SimpleDS, Objectify, etc.).
I was thinking that I should be able to delete some or all of the following JARs from my WEB-INF/lib folder:
datanucleus-appengine-[...].jar
datanucleus-core-[...].jar
datanucleus-jpa-[...].jar
geronimo-jpa_[...].jar
geronimo-jta_[...].jar
jdo2-api-[...].jar
But when I do, I get errors from Eclipse complaining that “The App Engine SDK JAR is missing in the WEB-INF/lib directory”.
Is it really necessary to retain all these (unused) JARs?
I don’t think you can delete them from the project (as you have said, eclipse starts to complain), but I’ve heard you don’t have to upload them to your app, as long as you upload from the command line. This has the advantage that at startup your app won’t have to load them up.
There are some details of uploading to app engine via the command line here and confirmation that you can do this here
If you manage to do this I would appreciate it it if you post links to the instructions you followed or post what you needed to do, as I have this on my todo list as well, but only got as far as seeing if it was possible. Thanks!