turn api with hibernate objects into service for multiple applications

i have an API that is being written for a large group of 40 or so applications to share.

my problem is currently they plan on having the API as a simple library included in each war file for each program. the problem thats going to occur is when two apps are running on the same instance with different versions of the api library. ive had a lot of problems in the past wi开发者_开发技巧th this.

i seem to remember a while ago something where i can wrap my library into an ear file or something and deploy it to tomcat to make it global. simply including it in the lib folder won't work because it will include hibernate systems that have to be deployed to allow the api methods to access the database. then in each application i would have an interface i can implement that allows me to call those api methods. very similar to local EJB3 but not as complex and didn't require an enterprise level server to implement.

anyone else remember something like this or was it a bad dream on my part?

You will have problems if you use a single jar shared by all the webapps, since it will then be impossible for two apps to use a different version of a library. But if each webapp has its own version of the library in its WEB-INF/lib, the container shouldn't have any problem: each webapp has its own classloader, which doesn't see the libraries of other webapps.