ArrayList - fail-safe or fail-fast iteration using iterator, listIterator, Enumeration and enhanced for loop.
iterator returned by ArrayList is fail-fast. Means any structural modification made to ArrayList like adding or removing elements during Iteration will throw java.util.ConcurrentModificationException.
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
/**
* Copyright (c), AnkitMittal JavaMadeSoEasy.com
*/
public class ArrayListTest {
public static void main(String args[]) {
// creates array with initial capacity of 10.
List<String> arrayList = new ArrayList<String>();
arrayList.add("ankit");
arrayList.add("javaMadeSoEasy");
System.out.println("-------use iterator-------");
// fail-fast
Iterator<String> iterator = arrayList.iterator();
while (iterator.hasNext()) {
arrayList.add("newEle"); // unComment to avoid ConcurrentModificationException
System.out.println(iterator.next());
}
System.out.println("-------use listIterator-------");
// fail-fast
ListIterator<String> listIterator = arrayList.listIterator();
listIterator.next();
listIterator.previous();
while (listIterator.hasNext()) {
arrayList.add("newEle"); // unComment to avoid ConcurrentModificationException
System.out.println(listIterator.next());
}
System.out.println("-------use Enumeration-------");
// fail-fast
Enumeration<String> listEnum = Collections.enumeration(arrayList);
while (listEnum.hasMoreElements()) {
arrayList.add("newEle"); // unComment to avoid ConcurrentModificationException
System.out.println(listEnum.nextElement());
}
System.out.println("-------use enhanced for loop-------");
//enhanced for loop is fail-fast
for (String string : arrayList) {
arrayList.add("newEle"); // unComment to avoid ConcurrentModificationException
System.out.println(string);
}
}
}
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