Question

As per standard book constructor is a special type of function which is used to initialize objects.As constructor is defined as a function and inside class function can have only two type either static or non static.My doubt is what constructor is ?

1.)As constructor is called without object so it must be static

  Test test =new  Test();//Test() is being called without object
   so must be static

My doubt is if constructor is static method then how can we frequently used this inside
constructor

Test(){
    System.out.println(this);
}

Does the output Test@12aw212 mean constructors are non-static?

Answer 1

Your second example hits the spot. this reference is available in the constructor, which means constructor is executed against some object – the one that is currently being created.

In principle when you create a new object (by using new operator), JVM will allocate some memory for it and then call a constructor on that newly created object. Also JVM makes sure that no other method is called before the constructor (that’s what makes it special).

Actually, on machine level, constructor is a function with one special, implicit this parameter. This special parameter (passed by the runtime) makes the difference between object and static methods. In other words:

foo.bar(42);

is translated to:

bar(foo, 42);

where first parameter is named this. On the other hand static methods are called as-is:

Foo.bar(42);

translates to:

bar(42);

Foo here is just a namespace existing barely in the source code.