Hadoop is built against, and includes, an older version of the Jets3t library - version 0.6.1.
The current version of the Jets3t library(as of March 2012) is 0.8.1. This new version includes many improvements such as support for "Requester-Pays" buckets.
Since hadoop includes a copy of the version 0.6.1 jets3t library, and since this version ends up early in the CLASSPATH, any Map Reduce application that wants to use the jets3t library ends up getting version 0.6.1 of the jets3t library. The MR application fails, usually with an error stating that the method signature of some method in the Jets3t library does not match.
It would be useful to enhance Jets3tNativeFileSystemStore.java to use the API published by the 0.8.1 version of the jets3t library.