* remove debt from CachingTest

https://sonarcloud.io/project/issues?fileUuids=AW3G0SevwB6UiZzQNqXR&id=iluwatar_java-design-patterns&open=AXK0Ozo--CiGJS70dLl0&resolved=falseSigned-off-by: NSubhrodip Mohanta <subhrodipmohanta@gmail.com>

* fixed few debts for Spatial Partition module

Mainly convertig Hashtable to HashMaps
Signed-off-by: NSubhrodip Mohanta <subhrodipmohanta@gmail.com>

* fixed some logger norms
Signed-off-by: NSubhrodip Mohanta <subhrodipmohanta@gmail.com>

* fixed few errors as it got mixed with the stash
Signed-off-by: NSubhrodip Mohanta <subhrodipmohanta@gmail.com>

* Moves saga to Java 11

* Moves semaphore to Java 11

* Moves servant to Java 11

* Moves serverless to Java 11

* Moves service-layer to Java 11

* Moves service-locator to Java 11

* Moves sharding to Java 11

* Moves singleton to Java 11

* Moves spatial-partition to Java 11

* Moves specification to Java 11

* Moves state to Java 11

* Moves step-builder to Java 11

* Moves strategy to Java 11

* Moves subclass-sandbox to Java 11

* Fixes checkstyle issues

* Reduces checkstyle errors in facade

* Reduces checkstyle errors in factory-kit

* Reduces checkstyle errors in spatial-partition

* Reduces checkstyle errors in state

* Reduces checkstyle errors in step-builder

* Add custom license header style in order to comply with Google's Checkstyle format

* Update license headers to comply with Google's Checkstyle format

* Spatial partition

* Update pom.xml

* Update Bubble.java - pmd

* Update Rect.java - pmd