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Collections in Java

CopyOnWriteArrayList: Iteration

Understand how to perform thread-safe iteration with CopyOnWriteArrayList in Java. Learn to use forEach with lambdas and the snapshot iterator that avoids ConcurrentModificationException. Discover why the iterator’s remove method is unsupported and how elements can still be safely removed during iteration without errors.

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Iteration using forEach()

We can use the forEach(Consumer<? super E> action) method to iterate over a CopyOnWriteArrayList. This method was added in Java 8 and takes a lambda expression of type Consumer as the parameter.

Java
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
public class CopyOnWriteArrayListDemo {
	public static void main(String args[]) {
		List<String> list = new CopyOnWriteArrayList<>();
		list.add("Apple");
		list.add("Banana");
		list.add("Orange");
		list.forEach(System.out::println);
	}
}

Iteration using iterator()

The iterator() method returns an iterator that provides a snapshot of the state of the list when the iterator was constructed. No synchronization is ...