An Iterator walks a collection one item at a time. next returns the item. hasNext says whether another item remains. Use iterator.remove if you need to delete the item you just read.
Do not call list.remove inside a for-each over the same list. That throws ConcurrentModificationException. The iterator's own remove is the safe way during a walk.
Example
hasNext is true twice. Each next call returns the next name and moves forward.
import java.util.ArrayList;
import java.util.Iterator;
public class Walk {
public static void main(String[] args) {
ArrayList<String> names = new ArrayList<>();
names.add("Meera");
names.add("Arun");
Iterator<String> it = names.iterator();
while (it.hasNext()) {
System.out.println(it.next());
}
}
}Most lesson code can use for-each and stay clearer. Reach for Iterator when the loop must remove items as it goes.
