Tell me about your experience with RxJava.

This question is quite straightforward. The interviewer is asking about your hands-on experience with the reactive programming theory, especially with the use of the RxJava or ReactiveX Java library. This could usually translate to any particular projects you've worked on that extensively used RxJava or any unique implementation of the library you've had to carry out.

When answering this question:

1. Try to quantify your experience with RxJava, for example, the number of projects you have used it on or how many years/months you’ve worked with it.
2. Explain what type of applications or features you have developed using RxJava.
3. Mention any challenges you faced using RxJava and how you solved them.
4. You can also talk about any innovative use of RxJava you have made during your experience.

I have about two years of experience working with RxJava. During this time, I've utilized it in 6 different projects, which were mainly Android Applications. One of the apps was a real-time chat app, where RxJava was used heavily for handling real-time data streams. Another significant project was an e-commerce app where I used RxJava for managing network requests and local database queries concurrently.

One of the challenges I faced while working with RxJava was debugging stream hierarchies when an error happened. It was initially difficult to pinpoint where the problems occurred in the stream. Over time, I learned to leverage the .debug() operator provided by RxJava, which would log the thread name and values at each emission point. I feel this is a superb way RxJava aids in debugging when things do not work as expected.

In the past three years, I've dealt extensively with RxJava in many of my backend projects. One of the significant projects was an IoT-based home automation system project that was developed in Java. Through this project, I integrated different devices and used RxJava to handle streams of data between these devices.

While the intricacies of RxJava were quite complex to grasp initially, the power it provided in coding was worth the time and effort. Dealing with multi-threading was made significantly more manageable by switching schedulers in RxJava, but mastering this concept took some time and hands-on practice. Overall, I have built a comprehensive understanding of how to deal with asynchronous data streams using RxJava, which has been immensely helpful in my projects."