Fix Hadoop-Common JavaDoc Error on branch-3.3.
In the PR(#4267) of
HADOOP-18224. Upgrade maven compiler plugin to 3.10.1, I found that hadoop-common has a lot of javadoc compilation errors. I fixed it on the trunk, hoping to backport these changes to branch 3.3. These changes will ensure that hadoop common moudle javadoc will pass in JDK11 compilation.