Program: Write an example for Collections.checkedCollection() method.

Collections.checkedCollection() method returns a dynamically typesafe view of the specified collection. Any attempt to insert an element of the wrong type will result in an immediate ClassCastException. Assuming a collection contains no incorrectly typed elements prior to the time a dynamically typesafe view is generated, and that all subsequent access to the collection takes place through the view, it is guaranteed that the collection cannot contain an incorrectly typed element.

package com.java2novice.collections;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class MyCheckedCollection {

	public static void main(String a[]){
		
		List myList = new ArrayList();
		myList.add("one");
		myList.add("two");
		myList.add("three");
		myList.add("four");
		Collection chkList = Collections.checkedCollection(myList, String.class);
		System.out.println("Checked list content: "+chkList);
		//you can add any type of elements to myList object
		myList.add(10);
		//you cannot add any type of elements to chkList object, doing so
		//throws ClassCastException
		chkList.add(10); //throws ClassCastException
	}
}

Checked list content: [one, two, three, four]
Exception in thread "main" java.lang.ClassCastException: Attempt to insert
			class java.lang.Integer element into collection with element type class java.lang.String
	at java.util.Collections$CheckedCollection.typeCheck(Collections.java:2202)
	at java.util.Collections$CheckedCollection.add(Collections.java:2243)
	at com.java2novice.collections.MyCheckedCollection.main(MyCheckedCollection.java:23)