Few people know exactly in what order a classloader will load packages.
For example, if there are two jars in a project, commons-logging-1.0.4.jar and commons-logging.jar, which one will be loaded first by the classloader?
: 38,015 commons-logging-1.0.4.jar 37,443 commons-logging.jar :
It is difficult to guarantee which one is loaded first, depending on the application server, so it is always better to use only one version of a jar:
: 38,015 commons-logging-1.0.4.jar :