I has confused for long times by the question: Should we use Apache frankly, the world-famous open source library?
   Sometimes I answer Yes and sometimes No. Why?
   On one hand, apache's library is powerful, creative, rich and can cover almost all your needs without any modifications;
   On the other hand, it's so negligent, and so all-purpose  that seems to be non-dedicated to your specified task, even sometimes it results in bad performance! for example, we found a problem from the ExtendedProperties class long times ago, while loading prop files inclusively, it open new file streams but never close them. this could cause fatal error on some operatin systems.
   With Log4j, an obvious problem in web applications is, after stopping your application, the log files still be hold by the running jvm and can't be deleted.

•  Enhanced url-processing mechanism

• Intelligible configuration mechanism