Question：Possibility of deadlock in "Database ServiceImpl"

[arjun12102019]

If an exception occurs while setting the schema in the method "queryDatabaseSchema", countDown() will not be called for that thread, resulting in a deadlock situation at "countDownLatch.await()"

and observed a minor readability issue using the full package name of "StringUtils" in "EasyStringUtils"

Please confirm my understanding of the deadlock situation so I can make changes and raise the PR.