29.3.2. Basic Nashorn Example

import javax.script.*;
public class ScriptExample {
    public static void main(String[] args) throws ScriptException {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("nashorn");
        engine.eval("print('Hello from JavaScript!');");
    }
}

This chunk introduces a very basic example of using the Nashorn JavaScript engine in Java. The program begins by importing the necessary classes from the javax.script package. It then defines a public class named ScriptExample with a main method that serves as the entry point. Within this method, an instance of ScriptEngineManager is created, which is responsible for managing script engines. Next, a ScriptEngine is obtained for the Nashorn JavaScript engine using the getEngineByName method. Finally, the eval method of the engine is called, which allows JavaScript code (in this case, a simple print statement) to be executed directly, displaying 'Hello from JavaScript!' on the console. This example demonstrates how to integrate and run JavaScript code within a Java application.

Think of it like a chef (Java) who can suddenly speak another language (JavaScript) to take instructions directly from a guest (the script). By understanding and executing these instructions, the chef can create dishes (dynamic applications) without needing to know how to cook every recipe beforehand. The Nashorn engine allows this seamless communication.

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