Logging question, what are the differences?

My question is related to various logging APIs. Basically, I would just like to know the differences between SimpleLog, Log4j, java.util.logging and NoOpLog. I am not expecting a long answer of what they really are, I am just interested to know under what situation would we be switching to a different kind of log API (as I have always thought that util.logging is the only logging utility that is available until I read a brief intro about other logging APIs).

[469 byte] By [SheepSheepa] at [2007-11-27 1:33:36]