Iterators are designed to easily change the collections that they loop through. The remove() method can remove items from a collection while looping.
Example
Use an iterator to remove numbers less than 10 from a collection:
import java.util.ArrayList;
import java.util.Iterator;
public class Main {
public static void main(String[] args) {
ArrayList<Integer> numbers = new ArrayList<Integer>();
numbers.add(12);
numbers.add(8);
numbers.add(2);
numbers.add(23);
Iterator<Integer> it = numbers.iterator();
while(it.hasNext()) {
Integer i = it.next();
if(i < 10) {
it.remove();
}
}
System.out.println(numbers);
}
}
Note: Trying to remove items using a for loop or a for-each loop would not work correctly because the collection is changing size at the same time that the code is trying to loop.
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