JavaScript and Java are two of the most popular programming languages used by developers today. Though their names sound similar, they are quite different in their concepts, uses, syntax and capabilities.
A Brief History
JavaScript and Java have distinct histories despite their similar names. Here is a quick look at their origins and evolution.
JavaScript
Brendan Eich created JavaScript in 1995. It was originally developed for Netscape Navigator to make web pages more dynamic and interactive. The language was first called LiveScript, but Netscape changed its name to JavaScript, hoping to capitalize on Java’s popularity at the time.
JavaScript gained widespread adoption when it became supported by all major web browsers. Today, it continues to be an essential technology that powers dynamic behavior and interactivity on websites and web applications.
Java
Java was developed by James Gosling and colleagues at Sun Microsystems, released in 1995. The aim was to create a language that could run on any device or operating system, known as the “write once, run anywhere” principle.
Java is a general-purpose, object-oriented programming language used to develop all types of applications, including desktop, mobile, web, enterprise, etc. It derives much of its syntax from C and C++ but has fewer low-level facilities. Many companies choose to outsource Java development to specialized firms or offshore teams.
Key Differences
Though they share C-like syntax, JavaScript and Java differ in some fundamental ways. Here are the major points of divergence.
Type of Languages
JavaScript is a scripting language used to make web pages interactive. Java is a general-purpose programming language used to develop all types of applications.
Execution Environment
JavaScript code is executed in a web browser. Java code needs a Java Virtual Machine (JVM) to execute.
Speed
JavaScript executes code line by line. Java first compiles source code into bytecode, which is then executed by JVM, making Java faster to execute.
Purpose
JavaScript adds interactivity and dynamic behavior to web pages and applications. Java is also used to develop all types of desktop, web, and mobile applications.
Syntax
Though the syntax of both languages is influenced by C/C++, JavaScript uses prototypes while Java uses classes and interfaces. The syntax varies significantly.
Static vs Dynamic
Java is a statically-typed language while JavaScript is a dynamic (loosely) typed language. Java requires defining variable types during declaration while JavaScript determines types during runtime.
Compilation
Java code needs to be compiled before execution. JavaScript code is interpreted without any compilation.
Similarities Between JavaScript and Java
- Both languages have C/C++-like syntax since they derive elements from these languages.
- Variables are declared before use in both languages.
- Conditional statements like if-else, switch, break etc., are available.
- Loops like while, do-while, for and for-each can be used.
- Both support comments in the code.
- Mathematical operators, logical operators, and bitwise operators exist in both.
- Methods can be defined in objects.
Uses of JavaScript and Java
JavaScript and Java have evolved to serve different primary purposes over the years.
Uses of JavaScript
As a lightweight, interpreted programming language, JavaScript powers the dynamic user-facing parts of web pages and applications. Its main use cases revolve around the front-end. JavaScript brings web pages to life through interactive elements like click interactions, animations, data visualizations. It enables validating form data before submission, updating page sections without full-page reloads through asynchronous communication behind the scenes.
Some very popular uses are: building single-page applications with frameworks like React and Vue, which offer fluid, mobile-app-like experiences, game development to render graphics/animations at high speed, and adding multimedia elements like playing audio and video right inside web pages. The versatility of JavaScript also allows it to extend beyond the browser-based front end. Node.js can execute back-end server-side code to build fast and scalable applications. JavaScript is widely adopted by startups and software products aiming for agile development.
Uses of Java
As a robust, statically typed language that compiles to platform-independent bytecode, Java is ideal for more complex and performance-critical applications. Its blazing-fast execution and vast ecosystem underpin many enterprise systems and mission-critical software. Java powers all types of desktop software, from media players to image editors. On the web, Java drives e-commerce sites, social networks, and banking platforms, which need to handle high traffic securely. It brings advanced capabilities like supporting multiple threads to enable parallel execution. The structured object-oriented code lends itself well to large projects where many developers collaborate.
On mobile, Java enables the development of full-fledged Android apps with excellent tooling support and libraries for device capabilities. The language continues to penetrate cutting-edge domains like machine learning, big data analytics and financial trading systems that need to churn huge volumes of data efficiently. Its hardware-near capabilities also allow integration with electronics and embedded devices.
This outlines the major differences and similarities between JavaScript and Java. While JS brings interactivity to the front end of websites and apps, Java powers full-fledged applications and backend server functionality. Understanding their distinct roles is important for developers looking to specialize or work across the stack.
Syntax Comparison
Though JavaScript and Java syntax have common origins in C++ and C, they have evolved differently over the years and have very distinct syntax constructs.
1. Hello World Program
// JavaScript
console.log(“Hello World”);
// Java
public class Main {
public static void main(String[] args) {
System.out.println(“Hello World”);
}
}
Even a simple Hello World program shows syntactic differences in structure, comment syntax, print statements, casing conventions, etc.
2. Variables
JavaScript uses dynamic typing, while Java uses static typing for variables.
// JavaScript
let count;
count = 10;
count = “Hello”;
// Java
int count;
count = 10;
count = “Hello”; // Error as count is integer type
3. Data Structures
JavaScript leverages prototypes, whereas Java relies on classes and interfaces for object-oriented code.
// JavaScript
function Person(name) {
this.name = name;
}
Person.prototype.walk = function() {
console.log(this.name + ” is walking”);
};
let person1 = new Person(“John”);
person1.walk();
// Java
public class Person {
private String name;
public Person(String name) {
this.name = name;
}
public void walk() {
System.out.println(this.name + ” is walking”);
}
}
Person person1 = new Person(“John”);
person1.walk();
4. Inheritance
JavaScript uses prototypal inheritance, while Java has class-based inheritance.
// JavaScript
function Animal(name) {
this.name = name;
}
Animal.prototype.eat = function() {
console.log(this.name + ” is eating”);
}
function Rabbit(name) {
Animal.call(this, name);
}
Rabbit.prototype = Object.create(Animal.prototype);
let rabbit = new Rabbit(“White Rabbit”);
rabbit.eat();
// Java
public class Animal {
private String name;
public Animal(String name) {
this.name = name;
}
public void eat() {
System.out.println(this.name + ” is eating”);
}
}
public class Rabbit extends Animal {
public Rabbit(String name) {
super(name);
}
public static void main(String[] args) {
Rabbit rabbit = new Rabbit(“White Rabbit”);
rabbit.eat();
}
}
This gives a side-by-side glance at how JavaScript and Java syntax differ in structure across basic building blocks.
Learning JavaScript and Java
Learning JavaScript
To learn JavaScript, start with basic client-side scripting and DOM manipulation before gradually moving towards:
- AJAX, Fetch API
- ES6+ concepts like arrow functions, promises
- Modern frameworks like React, Vue
- Node.js for server-side programming
- JavaScript testing frameworks like Jest
Resources for mastering JavaScript:
- Mozilla Developer Network (MDN)
- EloquentJavaScript
- JavaScript.info
Learning Java
To master Java, begin with grasping Object-Oriented concepts data structures and work your way up towards:
- Java database connectivity (JDBC)
- Multithreading and concurrency
- Collections framework
- Java IO, networking
- Enterprise Java – Servlets, JSP
- Frameworks like Spring, Hibernate
- JUnit testing
Resources for learning Java:
- Oracle Java Documentation
- JavaTPoint
- JournalDev Java Tutorials
The paths clearly diverge, so focus on the domain you want to specialize in.
Wrapping Up
- JavaScript and Java have very different backgrounds and use cases despite the seemingly similar names.
- JavaScript is simpler and beginner-friendly, but it is more structured and robust for large apps.
- Mastering both opens up full-stack opportunities to work across frontend, backend and several domain areas.
- JavaScript is essential for client-side scripting, while Java powers server-side application logic.
- Know when to use JavaScript to add interactivity and when to use Java to develop complex, scalable enterprise systems.
We hope this detailed guide helps differentiate between JavaScript and Java and throw light on their backgrounds, capabilities and learning paths for new programmers. Both continue to evolve and underpin a significant portion of the technology landscape.
