The default emacs behavior for the forward-paragraph and
backward-paragraph functions is to hop between blank lines in a source
code file. This breaks in java-mode in the presence of javadoc @clauses.
I sent a pull request to the js2-mode project (which also supports
javadocs, and thus the same error occurs) but it was rejected since they
told me it was an emacs bug.
Here's the pull request I sent the js2-mode authors:
Here's the video explanation I gave the js2-mode authors: