Sonar: Utility classes shouldn't have public constructor

Sonar: Utility classes shouldn't have public constructor

Fix 19 instances of Sonar issue "Utility classes should not have a
public constructor" labeled as Major. The rule descriptions says:
"Utility classes, which are a collection of static members, are not
meant to be instantiated. Even abstract utility classes, which can be
extended, should not have public constructors. Java adds an implicit
public constructor to every class which does not define at least one
explicitly. Hence, at least one non-public constructor should be
defined."

Change-Id: I5e17afe35bc44d02e238f5a1558dfcfb588c7f80
Signed-off-by: Lorand Jakab <lojakab@cisco.com>