This () constructor is not needed?

Question

There was class U1 extending class U. Class U was empty ...

In constructor U1 there was this first line, calling the constructor of the superclass ...

public U1(Plate plate, int order) { super(plate, order); ... } 

Now I want to delete the class U1 and do in class U everything that has been done in U1 so far ... So, now I will not need to call the constructor of the superclass, since the class U does not have any superclass ...

Is this(plate, order) unnecessary and can I omit it?

Here's how my U constructor would look like this:

 public U(Plate plate, int order) { this(plate, order); ... } 

Answer 1

This is not necessary, and I expect this to lead to a stack overflow, because you are calling the constructor itself inside the constructor.

Answer 2

This will result in a compilation error. JLS Section 8.8.7 states:

"This is a compile-time error for a constructor to directly or indirectly call itself through a series of one or more explicit constructor calls involving this ."

In this case, the constructor calls directly.

Answer 3

in the sample, as shown below, we get the error: call the recursive constructor,

 class TestConstruct{ public TestConstruct(){ this(); System.out.println("constructor of Test class"); }//end of constructor }//end of class TestConstruct public class AppConstruct{ public static void main(String[] a){ Test t = new Test(); }//end of main }//end of AppConstruct 

Answer 4

This is not to be missed. You must omit it, otherwise it will act as an infinite recursive call.

Answer 5

We call super () in the constructor to initialize the instance variables inherited from the superclass, so there is no need to call super () if there is no superclass - the java.lang.Object exception. If there are multi-constructors, we can do this () to call other constructors, but do not call the constructor itself, which causes the bad things that previous people talked about.