Question

Pretty easy question, but anyway: is there any reason to override default constructor like this:

public SomeObject(){
}

It is public. It is does not have any logic. So, is there necessary? I didn’t see the whole picture?

Appreciate all your help.

Answer 1

One reason to define an empty no-arg constructor is if there is also a non-default constructor and the no-arg constructor is still desired to be accessible (public or protected).

This is because any [other] constructor definition will prevent the automatic addition of the default no-arg constructor:

The compiler automatically provides a [public] no-argument, default constructor for any class without constructors.

(See the next bit in that link as well, where it talks about the default super constructor that will be called.)

Even if the no-arg constructor is never used manually, it can be important for other things, e.g. Serializable:

During deserialization, the fields of non-serializable classes will be initialized using the public or protected no-arg constructor of the class. A no-arg constructor must be accessible to the subclass that is serializable. The fields of serializable subclasses will be restored from the stream.