Welcome to your interview.
The question is on your right: Java OOP and Testing Concepts. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
Explain inheritance, polymorphism, method overloading, method overriding, interfaces, try/catch, serialization, and constructors in Java, and connect them to unit testing and integration testing.