[STORM-3850] Remove PMD exceptions

[bipinprasad]

What is the purpose of the change

mvn build creates a large number of repeated WARNING messages

Static Code Analyzer (using PMD plugin) reports a large number of errors.

Many of them are parsing errors by PMD plugin itself. This appears to be because the parse is assuming that the target source is below JDK 1.6.

(1) Fix this to assume JDK 1.8 source so that method references are properly parsed. (2) Fix the java code to remove PMD warnings

Changing the code to 1.8 may reveal new PMC exceptions that were hidden because of PMD plugin parser errors.

(3) Fix new java code PMD errors uncovered when target jdk is switched to jdk8 and even jdk11

How was the change tested

Build and unit test