Java Collections emptyIterator() Method

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Description

The Java Collections emptyIterator() method is used to get the empty iterator. Iterator is empty and its hasNext method always returns false. next() method call throws NoSuchElementException and remove() throws IllegalStateException.

Declaration

Following is the declaration for Java Collections emptyIterator() method.

public static <T> Iterator<T> emptyIterator()

Parameters

NA

Return Value

NA

Exception

NA

Getting Empty Iterator of Integers Example

The following example shows the usage of Java Collection emptyIterator() method to get an empty iterator of Integers. We've created an empty iterator using emptyIterator() method and then checked if iterator has elements or not.

 
package com.tutorialspoint;

import java.util.Collections;
import java.util.Iterator;

public class CollectionsDemo {
   public static void main(String args[]) {
      
      // create an empty list    
      Iterator<Integer> emptyIterator = Collections.emptyIterator();

      System.out.println("Created empty iterator, it has elements: "+emptyIterator.hasNext());
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Created empty iterator, it has elements: false

Getting Empty Iterator of Strings Example

The following example shows the usage of Java Collection emptyIterator() method to get an empty iterator of Strings. We've created an empty iterator using emptyIterator() method and then checked if iterator has elements or not.

 
package com.tutorialspoint;

import java.util.Collections;
import java.util.Iterator;

public class CollectionsDemo {
   public static void main(String args[]) {
      
      // create an empty list    
      Iterator<String> emptyIterator = Collections.emptyIterator();

      System.out.println("Created empty iterator, it has elements: "+emptyIterator.hasNext());
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Created empty iterator, it has elements: false

Getting Empty Iterator of Objects Example

The following example shows the usage of Java Collection emptyIterator() method to get an empty iterator of Student objects. We've created an empty iterator using emptyIterator() method and then checked if iterator has elements or not.

 
package com.tutorialspoint;

import java.util.Collections;
import java.util.Iterator;

public class CollectionsDemo {
   public static void main(String args[]) {
      
      // create an empty list    
      Iterator<Student> emptyIterator = Collections.emptyIterator();

      System.out.println("Created empty iterator, it has elements: "+emptyIterator.hasNext());
   }    
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result.

Created empty iterator, it has elements: false