Avoid problems with runtime-compiled ALIAS methods when people have set the JAVA_TOOL_OPTIONS environment variable.

Replace Thread#sleep() with CountDownLatch
Original patch by Davide Cavestro, with some modifications by myself

Issue 485: Database get corrupted when column is renamed for which check constraint was defined inside create table statement.

Fix the combination of updating a table which contains an LOB, and reading from the LOB at the same time.
Previously it would throw an exception, now it works.