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CollectionsExample.java
Output
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CollectionsExample.java
import java.util.ArrayList; import java.util.Collections; import java.util.List; /* Method: public static <E> List<E> checkedList(List<E> list, Class<E> type) Parameters: list - the list for which a dynamically typesafe view is to be returned type - the type of element that list is permitted to hold Returns: a dynamically typesafe view of the specified list. */ public class CollectionsExample { public static void main(String[] args) { List myList = new ArrayList(); myList.add("one"); myList.add("two"); myList.add("three"); myList.add("four"); System.out.println("myList : " + myList + "\n"); /* * Returns a dynamically typesafe view of the specified list. */ List chkList = Collections.checkedList(myList, String.class); System.out.println("Checked list : " + chkList + "\n"); /* * you can add any type of elements to myList object. */ myList.add(10); System.out.println("myList : " + myList + "\n"); /* * you cannot add any type of elements to chkList object, doing so * throws ClassCastException. */ chkList.add(10); System.out.println("Checked list : " + chkList + "\n"); } }
myList : [one, two, three, four] Checked list : [one, two, three, four] myList : [one, two, three, four, 10] 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$CheckedCollection.typeCheck(Collections.java:3037) at java.util.Collections$CheckedCollection.add(Collections.java:3080) at CollectionsExample.main(CollectionsExample.java:53)Click the below Image to Enlarge
Java : Collection Framework : Collections (CheckedList) |
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