Managing execution contexts

Because Play uses explicit concurrency control, controllers are also responsible for using the right execution context to run their action's code. Generally, as long as your actions do not invoke heavy computations or blocking APIs, the default execution context should work fine. However, if your code is blocking, it is recommended to use a distinct execution context to run it.

An application with two execution contexts (represented by the black and grey arrows). You can specify in which execution context each action should be executed, as explained in this section

Unfortunately, there is no non-blocking standard API for relational database communication (JDBC is blocking). It means that all our actions that invoke code executing database queries should be run in a distinct execution context so that the default execution context is not blocked. This distinct execution context has to be configured according to your needs. In the case of JDBC communication, your execution...