Samples for url to blog post

Few test cases to illustrate why hashCode implementation should be consistent and return the same value on every call.

To start tests ./gradlew test

Tested on

java version "1.8.0_91"
Java(TM) SE Runtime Environment (build 1.8.0_91-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)