How would you create an immutable object in Java? How do you feel about the type system of Java vs Javascript? What is a relational database? When would you use a nosql database instead of sql? What is MERN? What is a CDN, why would you use it? What is an ORM? When would you not use an ORM like Hibernate? What does Spring framework provide that core Java does not? Why use Mockito? What is the React lifecycle?