Not only that, but big iron level Java app servers like OracleAS have long been able to have "hidden" dependencies. So your Hibernate dependency can depend on o

Not only that, but big iron level Java app servers like OracleAS have long been able to have "hidden" dependencies. So your Hibernate dependency can depend on one version of, say, commons-lang, and your Spring dependency can depend on a different version. For many years this had to be done with tools that change the package names, but in modern app servers you can just specify this using configuration and they implement it with special class loaders. Only really causes a problem if your dependency returns instances of its dependency to callers and then your app needs a different version...