Reference type java

You don’t have to define a constructor for a class, but if you don’t define any constructor, the Java compiler will insert a default, no-argument constructor for you .

8 Answers. An empty constructor is needed to create a new instance via reflection by your persistence framework . If you don’t provide any additional constructors with arguments for the class, you don’t need to provide an empty constructor because you get one per default.

Every tutorial I saw said : every entity needs an empty constructor . But Java always give you a default invisible empty constructor (if you don’t redefine one). … But Java always gives you this empty constructor when you don’t redefine it (write an other one with parameters).