1. I see a lot of changes that are pure refactoring: like adding "final" to class members and variables, or removing "public", or reshuffling imports. I am not against your changes, it is just that they make merging the branch with trunk even more difficult, and obscure the nature of the new functionality.
2. JavaDoc for getReplicaVisibleLength() is confusing. Could you please also make it 3 lines rather than 1.
3. Does not need any of the changes.
4. Here you do multiple field and method renames, combined with reformatting. I am lost.
5. Why do you need to abstract getReplicaInfo()? It does not seem that SimulatedFSDataset actually need it anywhere, at least not yet.
6. You factored out a part of the code into a new method. I cannot see what the new changes are.
7. Please do not re-sort the imports
8. It is not necessary to remove public from method declaration and remove unused method.
9. No need to remove the private constructor.
Could you please revise your patch so that it only makes the essential changes.
If you want to refactor please do it in a separate patch applied to trunk.