Issue #273: Caching Patterns [new pattern]

Reformat Code According to Google Style Guide #224

#271 implements producer-consumer

Issue #273: Changed DB to internal Java data structure to avoid compilation errors + decrease in code coverage

A Warning for beginners in the Readme.

Add unit test to callback method

Update to singleton unit tests and lazy loading unit test

Themoffster master - unit test improvements

Merge branch 'master' of https://github.com/themoffster/java-design-patterns into themoffster-master

Conflicts:
	dao/pom.xml

Fix - Shutdown the ExecutorService in App so that the resources are c…

Fix - Shutdown the ExecutorService in App so that the resources are collected and the process can finish

I ran App.main(String[] args) in the 'double-checked-locking' module and the process does not terminate. This is because the executor service still has open threads. I'm not sure how the JUnit tests are run, but it seems they are handling the leftover resources themselves.

Also, minor modifications to Inventory for final fields are used since there is no state change around them, and added some more meaningful printing so the example is more clearly demonstrated

MonoState Pattern

Add additional unit tests to show that singletons can be created in single thread environment and multithread environment. Also add a test to demonstrate a whole with Singleton when instantiating using reflection

Add some logging. Tests pass locally but not on github?

Add additional unit tests to show that singletons can be created in single thread environment and multithread environment. Also add a test to demonstrate a whole with Singleton when instantiating using reflection

Fixed Reference to Parent POM