How a subclass which extends a superclass calls the builder of parent class

I have a parent class like

 class A{

    //Constructors only called by builder.

 public static class builder{
   //builder code.
   }
 }

 Class B Extends ClassA{
    //constrctor

 }

Now if i do in my test

 final classA dempClassA = new ClassB("pa开发者_开发技巧rameters here");

how can i call the builder now..?

Sorry guys the builder is a class...My mistake.

If I understand well what you're trying to say, you have the following situation:

public class ClassA {

    // Constructors only called by builder.

    public static class Builder {
        // builder code.
        public static void hello() {
            System.out.println("Hello");
        }

        public void hello1() {
            System.out.println("Hello1");
        }
    }
}

And you access it this way:

class ClassB extends ClassA {
    public static void main(String[] args) {

        ClassA.Builder.hello();
        ClassA.Builder builder = new Builder();
        builder.hello1();

    }
}

If you want to call that method from outside the A class then it shouldn't be private.

If you just want it to be part of the B creation process then you should do something like this:

class B extends A {

  public B() {
    super(); // invokes A's constructor
  }
}

class A {
  public A(){
    // use builder() here
  }
}

Make ClassA's builder method protected (rather than private), so they're visible to ClassB, then use an anonymous class to call it, like this:

ClassA tempClassA = new ClassB("parameters here") {
    {  
       // This block is called during construction
       builder(); 
    }
};

Since the builder (is that a class btw? or is the return type missing?) is static, you'd call it like A.builder(). And for it to be visible, you shouldn't make it private :)

Edit: since it is a class, you have several possibilities:

• if you need a new instance call new A.builder(...)
• if builder provides static methods (in which case the question would be why this is a class) call A.builder.someStaticMethod(...)