Nashorn is a JavaScript engine introduced in JDK 8 for high-performance JavaScript execution on the Java Virtual Machine (JVM). It allows developers to run JavaScript code seamlessly within Java applications. In this blog post, we will explore how Nashorn can be used to manipulate arrays and collections in Java.

Working with Arrays

Nashorn provides several built-in functions to manipulate arrays. Let’s take a look at some common operations.

Declaring an Array

var numbers = [1, 2, 3, 4, 5];

Accessing Array Elements

var firstElement = numbers[0];
var lastElement = numbers[numbers.length - 1];

Modifying Array Elements

numbers[2] = 10; // Update the value at index 2

Adding Elements to an Array

numbers.push(6); // Add an element at the end of the array
numbers.unshift(0); // Add an element at the beginning of the array

Removing Elements from an Array

numbers.pop(); // Remove the last element of the array
numbers.shift(); // Remove the first element of the array

Iterating over an Array

numbers.forEach(function(element) {
    print(element);
});

Working with Collections

Nashorn also provides functions to manipulate collections, such as ArrayList and LinkedList. Let’s see how we can work with collections using Nashorn.

Creating a Collection

var list = new java.util.ArrayList();

Adding Elements to a Collection

list.add("Apple");
list.add("Banana");
list.add("Orange");

Accessing Collection Elements

var firstElement = list.get(0);
var lastElement = list.get(list.size() - 1);

Modifying Collection Elements

list.set(1, "Grapes"); // Update the value at index 1

Removing Elements from a Collection

list.remove("Orange"); // Remove an element by value
list.remove(0); // Remove an element by index

Iterating over a Collection

list.forEach(function(element) {
    print(element);
});

Conclusion

Nashorn provides powerful tools to manipulate arrays and collections in Java, making it easier to work with JavaScript code within your Java applications. Whether you’re dealing with arrays or collections, Nashorn’s API offers a range of built-in functions to perform common operations efficiently.

By leveraging Nashorn’s capabilities, developers can seamlessly integrate JavaScript code into their Java projects, enabling them to take advantage of the best of both worlds. So next time you find yourself needing to manipulate arrays or collections in a Java application, consider giving Nashorn a try.

#java #javascript