Interview Q&A / Object-Oriented Programming

1. What is a constructor, and what is constructor chaining?

   A constructor is a special method with the class's name and no return type that runs when an object is created, to set its starting state. Constructor chaining is one constructor calling another, either in the same class with this(...) or in the parent class with super(...), so setup code is written once.

   BeginnerIn-depth3 min read
2. When does Java provide a default constructor, and when does it not?

   If you write no constructor at all, the compiler adds a public no-argument one. The moment you write any constructor yourself, the compiler stops adding it.

   BeginnerQuick answer1 min read