DERBY-6053 (Client should use a prepared statement rather than regular statement for Connection.setTransactionIsolation)

Sinnce Connection object is already synchronized, no need to use synchronized Hashtable, instead us HashMap.

Also parameterize HashMap object declaration for easier usage and tighter type checking by the compiler.



git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1443599 13f79535-47bb-0310-9956-ffa450edef68