Nashorn

Nashorn is a JavaScript engine developed by Oracle for the Java Virtual Machine (JVM), introduced in Java 8 as a replacement for the older Rhino engine. It enables developers to execute JavaScript code directly within Java applications, providing seamless interoperability between Java and JavaScript. Nashorn compiles JavaScript to Java bytecode at runtime, offering improved performance and integration capabilities for embedding JavaScript in Java-based systems.

Also known as: Nashorn JS Engine, Java Nashorn, JSR 223 Nashorn, Oracle Nashorn, Nashorn JavaScript

Why learn Nashorn?

Developers should learn Nashorn when building Java applications that require dynamic scripting, such as embedding JavaScript for configuration, plugins, or business logic rules, especially in enterprise environments where Java is the primary stack. It is particularly useful for scenarios like server-side scripting in web applications, testing frameworks, or tools that need to evaluate JavaScript expressions within a Java context, though its relevance has diminished with the deprecation in Java 11 and removal in later versions.

Learning Resources

• docs: Oracle Nashorn Documentation
• tutorial: Baeldung: Introduction to Nashorn
• video: Java 8 Nashorn Tutorial on YouTube
• book: Nashorn: The Definitive Guide (Book)