concept of objects

[bhavneet kaur]

       class print
{
   {
    System.out.println("initializer");
    } 
 public static void main(String a[])
 {
  System.out.println("main");
  print ob1=new print();
 }
}

output=main initializer
but when i dont create object output=main ??? how
can anyone explain

[Enkita mody]

Object Creation
Initialization Blocks

-hth

[bhavneet kaur]

i have read that link , as here there is no constuctor ,so a default constructor get created on creation of object which prints that initializer

[Stuart A. Burkett]

bhavneet kaur wrote:
but when i dont create object output=main ??? how

You've answered your own question.
You don't create an object therefore the object initialiser is not executed.

[bhavneet kaur]

it means whenever default costructor created it reads the whole program

[dennis deems]

bhavneet kaur wrote:
it means whenever default costructor created it reads the whole program

No. It means that initialization blocks are executed only when something is instantiated.

[Kevin Florish]

There is a bit more to initializer blocks, just to clarify them:

Say for instance we have classes A and B

public class A { 
    {
    System.out.println("A Object initializer"); 
    }
}
public class B extends A { 
    {
    System.out.println("B Object initializer"); 
    }
}
public class TestB {    
    public static void main(String[] args) {
        A a = new A();   
        B b = new B();   
    }   
}

Outputs:
A Object initializer
A Object initializer
B Object initializer

Because of the calls to 'super' when we instantaite a subclass.

[bhavneet kaur]

A object initializer executed two times because of inheritance concept ,right?

and secondly to say in one line initialization blocks are those that do not have main method ,suppose there are three classes in a program and one class would contain main so rest of the classes are initalization blocks??

[bhavneet kaur]

and also that are outside main

[Kevin Florish]

bhavneet kaur wrote:A object initializer executed two times because of inheritance concept ,right?

Indeed

bhavneet kaur wrote: and secondly to say in one line initialization blocks are those that do not have main method ,suppose there are three classes in a program and one class would contain main so rest of the classes are initalization blocks??

1) Initializer blocks can be static or non-static and are easy to spot as they have no name, just braces {} or static {}.
2) The main() method doesn't have to appear in your class at all. It is there so you can invoke other code from it, either using a command-line or some IDE to get things running.
3) If you have more than one class in your program, then generally you have a top-level class (nothing to do with main() method) and the other classes are some kind of nested class, but thats another topic