Will this constructor work ?

[Men Gumani]

class X { public X (X x) { }  }

Thanks.

[Ruben Soto]

Is there anything that makes you think it might not work?

[Men Gumani]

The reason I raise this question is that I am reading chap 7 and I see a constructor like this :

class X { public <X> X(X x) {} } 

I don't know if the one I asked will work or not, if you can explain at which stage the compiler knows type X is there and we can declare it, it would be great, even better if you can tell me the usage of such constructor.
Thanks again.

[Ruben Soto]

The usage of such a constructor is to be used in mock exams to confuse people. That's basically it. In the real world you shouldn't use obscure features of the language, but make your code easy to read and maintain.

The constructor you showed is equivalent to this one:

class X { public <T> X(T input) {} }   

[Men Gumani]

Oh? Sorry buddy, but you sure it is

 class X { public <T> X(T input) {} }    

not

 class X { public <T> X(X input) {} }    

[Ruben Soto]

Men Gumani wrote:Oh? Sorry buddy, but you sure it is

 class X { public <T> X(T input) {} }    

not

 class X { public <T> X(X input) {} }    

Men,

I think it's the way I explained. This test seems to support that:

/*
Output is:
1
*/

class X {
   public <X> X(X x) {
      X b = x;
      System.out.println(b);
   }
}

public class XTest {
   public static void main(String[] args) {
      new X(new Integer(1));
   }
}

[Men Gumani]

Thank you Ruben

[Ruben Soto]

No problem.