How to remove an element from collection using Iterator Example

We have learnt how to iterate a collection using iterator, now lets see how to remove a element from a collection while iterating itself. The remove() method of the iterator will let us remove the element from the underlying collection.

package com.javainterviewpoint;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class JavaIteratorExample_Remove
{
	public static void main(String args[])
	{
		//Create a List (tempList) 
		List tempList = new ArrayList();
		
		//Populating our list
		tempList.add("Java");
		tempList.add("Interview");
		tempList.add("Point");
		tempList.add("JavaIterator");
		tempList.add("Example");
		
		System.out.println("TempList before removing element");
		System.out.println(tempList);
		
		Iterator it1 = tempList.iterator();
		
		while(it1.hasNext())
		{
			if("Point".equals(it1.next()))
			{
				//remove() method will let us remove the element without any exception
				it1.remove();
			}
		}
		System.out.println("TempList after removing element");
		System.out.println(tempList);
	}
}

Output

TempList before removing element
[Java, Interview, Point, JavaIterator, Example]
TempList after removing element
[Java, Interview, JavaIterator, Example]

List itself has the remove() method when you try to modify a list while iterating it will throw you ConcurrentModificationException and hence it is safe to use the remove() method of the iterator

package com.javainterviewpoint;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class JavaIteratorExample_Remove
{
	public static void main(String args[])
	{
		//Create a List (tempList) 
		List tempList = new ArrayList();
		
		//Populating our list
		tempList.add("Java");
		tempList.add("Interview");
		tempList.add("Point");
		tempList.add("JavaIterator");
		tempList.add("Example");
		
		//Get the iterator object using iterator() method of the collection
		Iterator it = tempList.iterator();
		//hasNext() will return true if the collection has more elements
		while(it.hasNext())
		{
			if("Point".equals(it.next()))
				tempList.remove(3);
		}
	}	
}

Exception in thread "main" java.util.ConcurrentModificationException
 at java.util.AbstractList$Itr.checkForComodification(Unknown Source)
 at java.util.AbstractList$Itr.next(Unknown Source)
 at com.javainterviewpoint.JavaIteratorExample_Remove.main(JavaIteratorExample_Remove.java:26)