The patch doesn't appear to include any new or modified tests. Please justify why no new tests are needed for this patch. Also please list what manual steps were performed to verify this patch.
This patch is a removal of an annotation that suppresses a warning, so no new tests are required. With the annotation's removal, there are still no compilation warnings for the Dispatcher interface. I manually ran the unit tests in hadoop-yarn-common and they all passed.
adoop-yarn-project/hadoop-yarn/hadoop-yarn-common in trunk has 1 extant Findbugs warnings.
Unrelated to this patch, as it's a potential NP in a different class (org.apache.hadoop.yarn.logaggregation.AggregatedLogFormat$LogValue)