Reference type java

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.

Providing an empty default constructor( private ) is necessary in those cases when you don’t want an object of the class in the whole program . For e.g. the class given below will have a compiler generated default empty constructor as a public member . As a result, you can make an object of such a class.

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).