Click here to watch in Youtube :
https://www.youtube.com/watch?v=33wMCTcvm_g&list=UUhwKlOVR041tngjerWxVccw
HashMapFailFastExample.java
HashTableFailFastExample.java
https://www.youtube.com/watch?v=33wMCTcvm_g&list=UUhwKlOVR041tngjerWxVccw
HashMapFailFastExample.java
import java.util.HashMap; import java.util.Iterator; import java.util.Set; public class HashMapFailFastExample { public static void main( String[] args ) { HashMap<Integer, String> hashMap = new HashMap<Integer, String>(); hashMap.put(1, "Apple"); hashMap.put(2, "Ball"); hashMap.put(3, "Cat"); System.out.println("hashMap : " + hashMap); Set<Integer> keys = hashMap.keySet(); /* * Iterator in the HashMap/Hashtable is fail-fast */ Iterator<Integer> iterator = keys.iterator(); while( iterator.hasNext() ) { Integer key = iterator.next(); /* * Throw ConcurrentModificationException if we modifies the map * structurally by adding or removing any element except Iterator's * own remove() method. */ hashMap.put(4,"Dove"); System.out.println("key : " + key); } } }
Output
hashMap : {1=Apple, 2=Ball, 3=Cat} key : 1 Exception in thread "main" java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429) at java.util.HashMap$KeyIterator.next(HashMap.java:1453) at HashMapFailFastExample.main(HashMapFailFastExample.java:28)
import java.util.HashMap; import java.util.Iterator; import java.util.Set; public class HashMapFailFastExample { public static void main( String[] args ) { HashMap<Integer, String> hashMap = new HashMap<Integer, String>(); hashMap.put(1, "Apple"); hashMap.put(2, "Ball"); hashMap.put(3, "Cat"); System.out.println("hashMap : " + hashMap); Set<Integer> keys = hashMap.keySet(); /* * Iterator in the HashMap/Hashtable is fail-fast */ Iterator<Integer> iterator = keys.iterator(); while( iterator.hasNext() ) { Integer key = iterator.next(); /* * Throw ConcurrentModificationException if we modifies the map * structurally by adding or removing any element except Iterator's * own remove() method. */ hashMap.put(4,"Dove"); System.out.println("key : " + key); } } }
Output
hashtable : {3=Cat, 2=Ball, 1=Apple} 3 2 1 hashtable : {4=Dove, 3=Cat, 2=Ball, 1=Apple}
To Download CollectionFailFastDemoApp Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/CollectionFailFastDemoApp.zip?attredirects=0&d=1
See also:
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