More a note for myself than anything, but it does look to be a useful library:

Commons Transaction aims at providing lightweight, standardized, well tested and efficient implementations of utility classes commonly used in transactional Java programming. Initially there are implementations for multi level locks, transactional collections and transactional file access. There may be additional implementations when the common need for them becomes obvious. However, the complete component shall remain compatible to JDK1.2 and should have minimal dependencies.

I believe that this is an off-shoot of the Jakarta-Slide WebDAV package. I do wonder why people continue to keep JDK1.2 compatiblity, though. I think even Websphere has moved on from that now, so I don't think there can be many environments left with only JDK1.2.