JTX supports multiple resource types, but its most efficient with single resource type, such as relational database. Therefore, there is whole layer build on top of generic JTX classes that serves just to simplify use and usage of transaction over databases.
But that is not all. Transactions, in general, are a perfect example of scattered logic, that can be encapsulated via aspects. With help of Proxetta, JTX can be applied on methods that are annotated with @Transaction annotation.
In most applications we would have only two types of transactions: one that only read and one that allows writing data. @Transaction annotation by default matches read-only transactions, meaning that on every place where read-write transaction is needed, user have to write this with annotation elements.
To reduce this boilerplate code, it is possible to define custom annotation that takes different default values.