I found out how to get the remote HEAD (FETCH_HEAD).
Now my Code is as follows:
git.fetch().call();
Repository repo = git.getRepository();
ObjectId fetchHead = repo.resolve("FETCH_HEAD^{tree}");
ObjectId head = repo.resolve("HEAD^{tree}");
ObjectReader reader = repo.newObjectReader();
CanonicalTreeParser oldTreeIter = new CanonicalTreeParser();
oldTreeIter.reset(reader, head);
CanonicalTreeParser newTreeIter = new CanonicalTreeParser();
newTreeIter.reset(reader, fetchHead);
List<DiffEntry> diffs= git.diff().setShowNameAndStatusOnly(true)
.setNewTree(newTreeIter)
.setOldTree(oldTreeIter)
.call();
for(DiffEntry entry : diffs) {
System.out.println(entry.toString());
}
It shows me remote changes like I wanted, but it works not correct. If I create a new File in my working-copy and commit the file (without to push), then the diff show me that the new file is deleted in the FETCH_HEAD.
How can I filter this false delete messages?