Ojdbc14.jar - which will use oracle's or weblogic

Question

Hi - I have a doubt on the JDBC connection. I am seeing ojdbc14.jar in weblogic's path and as well as Oracle's path. But during creating connection pool, which ojbc jar will be used by java application.

Answer 1

Yes but we're talking an enterprise environment hereOk. But that doesn't change what I said.
A class is loaded from a 'class path' which is defined from the context of the the class loader.
IF that context is the VM itself then the first jar wins.
IF that context is something like the url class loader then the first jar wins.
IF that context is something like a real custom class loader then it would need to be really odd for it to find some classes in the first jar but skip that same jar to then load classes (that were in the first jar) from the second jar. But even supposing that is the case and the jar is the same jar then there is no functional difference.
IF the jars are DIFFERENT and it some how loads classes that are incompatible, then that causes problems. As an example.
1. The second jar contains class A but jar one doesn't and the App calls A.
2. A (from jar two) calls B which exists in both jars, but will be loaded from the first jar (because it is first.)
3. B is different in the two jars.
Given the above it doesn't require any unusual in a class loader to cause a problem either. Any class loader would load the wrong classes in that case.
With classpath isolation turned on ( = every application runs in its own protected classloader environment) you don't know how many times I saw resources being loaded into two different classloaders and conflicting with each other under JBossNot sure what you mean by 'resource' but of course the classes themselves do not conflict with eash other when loaded into different class loaders. Conversely if there are limited access resources on a computer (such as a dedicated server port) and you load two classes via different class loaders then there will be a problem. But that is because two class loaders are in play and not because of the order in a class path.