Major Description
TransactionIds are currently empty. Java-doc of TransactionId states, that the UUID it holds, equals that of the current Interaction, and that the sequence counter keeps track of the transactions closed within the current Interaction.
Also TransactionId needs a new field, that holds the name of the persistence-context the current transaction belongs to, which should account for (not yet supported) cases, when multiple persistence layers coexist within Spring's application context.