corejava-OOPs: Why Parent class constructor is automatically called in child class constructor?

First of all we should have a look on inheritance concept, whenever we extend the class, the class´s behaviour is automatically comes under the derived class from base class.
Let´s consider an example:
class A
{
A()
{
System.out.println("Hello Constructor A");
}
}
class B extends A
{
B()
{
System.out.println("Hello Constructor B");
}
}
class C
{
public static void main(String args[])
{
B b1 = new B();
}
}

if we create the object of B class in class C, whenever Object initialized, constructor is called.
Class B constructor calls it´s super class constructor. super() is provided by java compiler in each subclass constructor, therefore firstly super class constructor is invoked.