add @NonNull annotation at generic type

[JSpiner]

New feature suggestion.

How about adding @NonNull to the generic argument?
Since rxjava2,
it is impossible to emit null.
Therefore, there is no null in upstream and downstream.
It may be added except in the case of ReplySubject::getValue.

[ZacSweers]

This requires RxJava be built against java 8. That said, with Android Gradle Plugin 3.2 bringing in D8 and its desugaring, the android library community is moving toward Java 8 now. Maybe that can be considered here too

[akarnokd]

RxJava is set to support Android 2.3+ through Java 6. Would such old runtimes still work?

[ZacSweers]

With the D8 tool, these would be stripped at runtime and just be present for static analysis tools

[JSpiner]

However, @NonNull can be added separately from the java8 issue.
Can I take it?

[ZacSweers]

It cannot, Type Annotations are a Java 8 language feature. Also, in general, much more of a fan of assuming nonnull is the default and only indicating nullable types with @Nullable

[yzhong52]

To add to this, when using rxJava2 in Kotlin, we will get this warning:

"Declaration has type inferred from a platform call, which can lead to unchecked nullability issues. Specify type explicitly as nullable or non-nullable."

since it is missing the null vs non-null annotation, which is a bit annoying to work with.