A possible alternative to the former approach (or an improvement) is the use of the following call:

RxJavaPlugins.setErrorHandler(...);

It will set a global handler for all the exceptions (or errors) that weren't caught by the mechanisms provided by the Observable flow.

Since RxJavaPlugins.setErrorHandler consumes the Consumer<Throwable> interface, we might as well plug in the class we just created to do the actual handling of the errors:

RxJavaPlugins.setErrorHandler(ErrorHandler.get());

Now, all the errors will go through this final handler if they aren't captured earlier.