Decrypting the connection between JavaScript and Java

Although JavaScript and Java have the same name, they are essentially different. The connection between them is mainly reflected in: similarity in names, both developed by Sun Microsystems. Syntax similarity, use semicolon to end statements, supports objects and classes. They are created for different purposes, Java is used for general programming and JavaScript is used for web interaction. JNI can be used to call Java code in JavaScript. JavaScript code can be used in Java using a JavaScript engine.

The connection between JavaScript and Java

Introduction

Although JavaScript and Java both has the word "Java", but they are completely different programming languages. However, they do relate in some ways. This article will explore their connection in depth and illustrate it through practical cases.

Name similarity

The names of JavaScript and Java are similar because they were both developed by Sun Microsystems. In 1995, Sun Microsystems was the first to launch Java, and then JavaScript in late 1995. JavaScript was originally named LiveScript, but was later renamed to catch up with Java.

Syntax Similarities

JavaScript and Java have some syntax similarities. For example, they both use a semicolon (;) to terminate statements, and both support objects and classes. This similarity makes learning both languages ​​easier, especially for those who are familiar with Java.

Created for different purposes

Despite these similarities, JavaScript and Java were created for different purposes. Java is a general-purpose programming language used for creating desktop applications, web applications, and mobile applications. JavaScript is an interpreted language commonly used to add interactivity to web browsers.

Practical case

Calling Java code in JavaScript

You can use Java Native Interface (JNI) to call it in JavaScript Java code. JNI is an API that allows Java code to interact with other languages, including JavaScript. The following is a simple example:

// Java代码
public class MyClass {
    public static void main(String[] args) {
        System.out.println("Hello from Java!");
    }
}

// JavaScript代码
const jni = Java.type("java.lang.Runtime");
jni.getRuntime().exec("java MyClass");

This code calls Java code in JavaScript to print out the "Hello from Java!" message.

Using JavaScript engine in Java

You can also use JavaScript engine to use JavaScript code in Java. The most popular JavaScript engine is Rhino. Here is an example:

// Java代码
import org.mozilla.javascript.*;

public class Main {
    public static void main(String[] args) {
        Context context = Context.enter();
        Scriptable scope = context.initStandardObjects();
        Object result = context.evaluateString(scope, "1 + 2", null, 1, null);
        System.out.println(result);
    }
}

This code uses the JavaScript engine in Java to calculate 1 2 and print out the result 3.

Conclusion

While JavaScript and Java share the same name and some syntax similarities, they are different programming languages ​​designed to serve different purposes. However, the connection between them allows developers to seamlessly interact code between different languages.

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