Fix more sonars in feature-server-pool

Addressed the following sonars:
- move fields from "interface" to "class"
- don't always return the same value
- remove commented-out code
- make constants "final"
- don't synchronize on parameters

Issue-ID: POLICY-2546
Change-Id: If2d410664d956a7efabf3a4dbef96bbf7d24de5e
Signed-off-by: Jim Hahn <jrh3@att.com>
8 files changed