Fix bug in Cache Data Export caused by Geode's JVM Shutdown Hook

[jxblum]

Apache Geode prematurely closes all cache objects and pulls the rug out from any application, framework and tool's feet.

Geode registers a JVM Shutdown Hook that closes all cache objects (e.g. Regions) before a framework, such as Spring, has an opportunity to perform resource clean up, such as in Spring Container Lifecycle callbacks, such as DisposableBean. This is potentially dangerous and definitely naive on Geode's part.

Fortunately, Geode uses a JVM System Property to control the registration of the JVM Shutdown Hook, and prevent the hook from prematurely closing the cache so that application/framework/tools have an opportunity to perform or resource release and clean up tasks that Geode unaware of.

[jxblum]

Argh!!!

Unfortunately, this (dumb) block of code requires Spring to somehow intercept or set the JVM System Property before Geode's InternalDistributedSystem class is loaded!

Currently exploring the feasibility of Spring Boot's AutoConfigureBefore annotation(s)...

[jxblum]

This will need to be in something like a Spring Framework BeanFactoryPostProcessor, or more appropriately, a Spring Boot EnvironmentPostProcessor since this (Geode) JVM System Property needs to be set early (before a class load on InternalDistributedSystem which happens when the cache is created)!