Facebook Java Developer Mock Interview

Practice 20 Facebook Java Developer interview questions covering system design, scalability, and backend engineering.

Question 12 of 20

What is a marker interface, and how do you use it when writing Java code for the Facebook environment?

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William Swansen has worked in the employment assistance realm since 2007. He is an author, job search strategist, and career advisor who helps individuals worldwide and in various professions to find their ideal careers.

The fact that this is a technical question is obvious since it asks you to define a term and then discuss how it is used. Make sure you answer each part of the question in the order asked. This will help the interviewer follow your answer and confirm that you are listening to their questions during the interview.

William Swansen

"A marker interface, as it is used in Java, is a design pattern which provides runtime information about the objects within the program. It also enables the addition of metadata with a class even though the Java language doesn't implicitly support metadata. When coding in Java, the marker interface is used as an interface which doesn't specify a method."

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