I wanted to open this directly as a JIRA to follow-up on FLINK-3042, however my account (aalexandrov) does not seem to have the necessary privileges, so I will post this to the dev list instead.
The current approach for registration of custom `TypeInformation` implementations which relies exclusively on annotations. Consequently, it will be very tedious to create a custom `TypeInformation` for types that are pulled and used within a project from an external library. For example, if I have a project structure such as ``` my-project // uses FancyContainer<A> `- flink-core `- ext-library // defines FancyContainer<A> ``` I will not be able to modify `FancyContainer.java`. A workaround that might work (I have not tested it yet) is to use `javassist` to attach the annotation prior to job assembly, but IMHO a much clearer solution would be to extend the `ExecutionEnvironment` with something like ```java env.getConfig().registerTypeInfoFactory(Class<?> type, Class<? extends TypeInfofactory<?>> factory) ``` Regards, Alexander
