Apply simple sonar fixes

Apply simple sonar fixes

Note: A number of these were identified, by SonarLint, in the Test
classes, which are not typically scanned by Sonar.

Removed unnecessary imports.
Removed unneeded "throws Xxx".
Replaced lambda with method references.
Replaced duplicate strings with constants.
Replaced try-fail-catch with assert-j methods to eliminate sonar
complaints about duplicate failure messages.
Added missing @Override annotations.
Use map.computeIfAbsent() where appropriate.
Also fixed some minor checkstyle issues.
Removed unneeded "volatile" declarations.
Replaced some if-else constructs with "?:" construct, per sonar.
Replaced Object.wait() with CountDownLatch.await(); according to sonar
(and javadocs), Object.wait() can return due to "spurious wakeups".
Fixed issue whereby CryptoUtilsTest wouldn't run in my Eclipse.

Change-Id: Ib6b71ed65662cfd6209400dac57ed69279bf29ec
Issue-ID: POLICY-1791
Signed-off-by: Jim Hahn <jrh3@att.com>