Annotate methods that return a definitely null value with @Nullable

We intend to enable the ReturnMissingNullable errorprone pattern in
Gerrit core and this fixes the current issues.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I676195e33e7c4400f8ad751157782a7e262c9243
8 files changed
tree: 513150e249c8c985810282dd0981bdd8c685df89
  1. .settings/
  2. src/
  3. .gitignore
  4. .mailmap
  5. BUILD
  6. LICENSE