HADOOP-10101 upgraded the guava version for 3.x to 21.
Guava is broadly used by Java projects that consume our artifacts. Unfortunately, these projects also consume our private artifacts like hadoop-hdfs. They also are unlikely on the new shaded client introduced by
HADOOP-11804, currently only available in 3.0.0-alpha2.
We should shade Guava everywhere to proactively avoid breaking downstreams. This isn't a requirement for all dependency upgrades, but it's necessary for known-bad dependencies like Guava.