{
final Tree subC = root.addTree("sub-c");
subC.addFile("empty").setId(cFileId2);
subC.setId(ow.writeTree(subC));
}
newTree = ow.writeTree(root);
}
final TreeWalk tw = new TreeWalk(db);
tw.reset(new ObjectId[] { oldTree, newTree });
tw.setRecursive(true);