Iterators on Multiple Collections in Parallel in Java

The following example code demonstrates Iterators on Multiple Collections in Parallel in Java.

Here’s an example of how to demonstrate the iteration over multiple collections in parallel in Java.

import java.util.*;

public class Main {
  public static void main(String[] args) {
    List<String> names = Arrays.asList("John", "Jane", "Jim");
    List<Integer> ages = Arrays.asList(30, 25, 35);

    // Using Iterator
    Iterator<String> nameIt = names.iterator();
    Iterator<Integer> ageIt = ages.iterator();
    System.out.println("Using Iterator:");
    while (nameIt.hasNext() && ageIt.hasNext()) {
      String name = nameIt.next();
      Integer age = ageIt.next();
      System.out.println(name + ", " + age);
    }

    // Using forEach and Lambda expression
    System.out.println("\nUsing forEach and Lambda expression:");
    Iterator<String> nameIt2 = names.iterator();
    Iterator<Integer> ageIt2 = ages.iterator();
    names.forEach(name -> {
      if (nameIt2.hasNext() && ageIt2.hasNext()) {
        Integer age = ageIt2.next();
        System.out.println(name + ", " + age);
      }
    });
  }
}

In this example, two collections names and ages are created to store the names and ages of people, respectively.

The first example demonstrates how to use two separate Iterator objects to traverse the names and ages collections in parallel. The hasNext method is used to check if there are more elements in each collection and the next method is used to retrieve the next element in each collection.

The second example demonstrates how to use the forEach method with a Lambda expression to traverse the names collection, while using another Iterator object to traverse the ages collection in parallel.

Further Reading