Ensure adequate time has elapsed before running System.gc() again using
System.currentTimeMillis().
Add RepositoryManager#isInitialized
Add RepositoryProvider to manager the RepositoryManagers and add
shutdownHook to call RepositoryManager#shutDown(), which calls
Repository#shutDown()
Check for channel close instead of catching ClosedChannelException
Add @since 2.7.0
Remove getConnection(String)
Only call Repository#shutDown() if Repository#isInitialized() returns
true and only return RepositoryManager#getInitializedRepositories() if
Repository#isInitialized() returns true
Add inline comment as suggested
Throw IllegalStateException (instead of NPE) when manager is used after
it has been shutdown (or before initialization)
Merged in SES-1732 (pull request #69)

Use Runtime#addShutdownHook to Try and Cleaning Shutdown Repositories
Merged in SES-1731 (pull request #68)

Ensure adequate time has elapsed before running System.gc() again using