Question

Describe/define/explain
a. The relationship between Java's Iterable and Iterator interfaces
b. An inner class
c. An anonymous inner class
d. The functionality of an Iterator remove method

Answer 1

a. The relationship between Java's Iterable and Iterator interfaces

• Iterable is to be applied to class that can be iterated
• An iterator is a way of allowing some to loop through a collection of data.
• In short itreator will return the current status of iteration in object and we can check next element by using method hasNext();

public interface Iterable<T>

{

    Iterator<T> iterator();

}

public interface Iterator<E>

{

    boolean hasNext();

   …

   …

    void remove();

}

1. An inner class
   • This is one of access security of java.
   • One class can be made private member of class
   • We can create inner class by simply writing it in outer class.
   • Generally we create class as Inner class whose object we don’t need explicitly but it is useful in outer class

Class outer{

Private class Inner

{

//data members and methods of Inner class

}

}

1. An anonymous inner class
   • An inner class declared without name is anonymous .
   • They are declared and instantiated at same time.
   • Generally, they are used whenever we need to override the method of a class or an interface.

Eg

abstract class A{

abstract void fun();

}

class Anonymous_Inner{

public static void main(String args[]){

A obj=new A(){

void fun(){System.out.println("Testing ");}

};

obj.fun();

}

}

1. The functionality of an Iterator remove method

• Used to remove object which are being iterator.
• Need to implement by program