Building microservices with Nashorn and Java

06 Oct 2023

In today’s fast-paced world of software development, microservices architecture has become a popular choice for building scalable and maintainable applications. Microservices enable developers to break down complex monolithic applications into smaller, modular services that can be developed, deployed, and scaled independently.

One interesting approach to building microservices is by leveraging Nashorn, the JavaScript engine embedded in Java. Nashorn allows developers to write server-side JavaScript code that can be seamlessly integrated into their Java applications. In this blog post, we will explore how to build microservices using Nashorn and Java.

What is Nashorn?

Nashorn is a lightweight, high-performance JavaScript engine introduced in Java 8. It provides seamless interoperability between Java and JavaScript, allowing developers to write JavaScript code that can directly call Java APIs and vice versa. This makes it a powerful tool for building polyglot applications that combine the strengths of both Java and JavaScript.

Developing Microservices with Nashorn

To build microservices with Nashorn, we can follow these steps:

Design the microservice: Define the functionality and boundaries of the microservice. This includes identifying the endpoints, input/output formats, and any integration points with other services.
Write the JavaScript code: Use Nashorn to write the business logic of the microservice in JavaScript. Nashorn provides access to Java APIs, allowing you to utilize the vast ecosystem of Java libraries and frameworks within your JavaScript code.
```
// Example JavaScript code using Nashorn
var express = Java.type('com.example.Express');
var app = express();
   
app.get('/api/hello', function(req, res) {
  res.send('Hello, world!');
});
   
app.listen(8080);
```

Embed the JavaScript code in a Java application: Create a Java application that embeds the Nashorn engine and loads the JavaScript code. This allows you to run the JavaScript code as part of your Java application.

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
   
public class Microservice {
    public static void main(String[] args) throws ScriptException {
        ScriptEngineManager engineManager = new ScriptEngineManager();
        ScriptEngine engine = engineManager.getEngineByName("nashorn");
        engine.eval("YOUR_JAVASCRIPT_CODE_HERE");
    }
}

Build and deploy the microservice: Build the Java application and package it with the embedded JavaScript code. Deploy the microservice to a container, cloud platform, or serverless environment.
```
$ mvn clean package
$ java -jar your-microservice.jar
```

By following these steps, you can leverage the power of Nashorn to build microservices that combine the best of Java and JavaScript. This approach allows you to take advantage of the mature Java ecosystem while also benefiting from the flexibility and expressiveness of JavaScript.

Conclusion

Building microservices with Nashorn and Java offers an innovative approach to developing scalable and modular applications. By seamlessly integrating JavaScript code with Java, developers can leverage the strengths of both languages to create powerful microservices. With the ability to access Java libraries and frameworks, Nashorn provides a compelling solution for building polyglot applications.

Give it a try and start exploring the possibilities of building microservices with Nashorn and Java!

What is Nashorn?

Developing Microservices with Nashorn

Conclusion

#Nashorn #Microservices