servlets - Tomcat - starting webapps in a specific order

Question

I know that Tomcat and the Servlet spec do not support starting webapps in a particular order.

However, this seems to me like a common use case, and I'm wondering if someone has discovered a clever workaround for it.

I have webapp A which uses Spring Remoting to expose a shared service, of which webapp B is a client. Webapp B cannot initialize unless webapp A is running. However, my Tomcat is always starting the webapps linearly, starting with webapp B.

For infrastructure reasons I have to have these running on the same Tomcat server.

Any ideas?

Thanks, Roy

UPDATE -

Turns out that in my particular case, order doesn't matter. The reason is this: say I use one of the methods below to start app A before app B. So app A starts, but, since Spring remoting is using the HTTP Invoker, the HTTP port is not yet open (it won't open until all apps are started). So A will start, and B will hang, because the port it's looking for is not yet available. Doh.

End result was two separate Tomcat instances.

Answer 1

We have the same problem and to solve it we're relying on the fact (slippery, I know) that applications are started in the order they are defined in <tomcat_home>/conf/server.xml.

This of course has a disadvantage of hardcoding apps in the server.xml but we can live with it.