What is an Applet?

An Applet is a small application designed to run within a larger application or web browser, providing specific functionality or features. Applets are typically written in Java and executed within a Java Virtual Machine (JVM) installed on the host computer, allowing them to be platform-independent. Historically, Java applets were commonly used on the internet to provide interactive features on web pages, such as animations, games, and other dynamic content. However, with the evolution of web technologies and concerns over security, the use of applets has significantly declined.

Role and Purpose of Applets

The primary roles and purposes of applets include:

  • Web Page Enhancement: Enhancing web pages with interactive content and dynamic features impossible with HTML alone.
  • Cross-Platform Compatibility: Running the same applet code on any device or operating system with JVM support, ensuring broad accessibility.
  • Client-Side Processing: Performing computations and operations on the client side, reducing server load and network traffic.

How Applets Work

  • Creation: Developers write applets using the Java programming language and compile them into bytecode.
  • Embedding: The bytecode is embedded into an HTML page using the <applet> tag or the newer <object> tag.
  • Execution: When a user visits the web page, the browser, with the help of a Java plugin, loads and executes the applet within the JVM.

Challenges and Decline of Applets

  • Security Concerns: Applets have faced numerous security issues, leading to browser and security restrictions on their execution.
  • Performance Issues: Loading and running applets can slow down web page performance, leading to a poor user experience.
  • Deprecation: Major web browsers have phased out support for the plugins required to run applets, and Oracle officially deprecated the Java browser plugin in JDK 9.
  • Alternatives: The rise of modern web technologies like HTML5, CSS3, and JavaScript frameworks has provided more secure and efficient ways to achieve the dynamic and interactive web experiences that applets once offered.

Alternatives to Applets

With the decline in the use of applets, developers have turned to alternative technologies to create rich, interactive web content:

  • HTML5: Offers native support for multimedia, animations, and graphical content without external plugins.
  • JavaScript and CSS3: Enable dynamic content and responsive designs, enhancing user interaction and visual appeal.
  • WebAssembly: Provides a way to run code written in multiple languages on the web at near-native speed, with client-side execution.
  • Frameworks and Libraries: Tools like React, Angular, and Vue.js facilitate the development of complex, single-page applications (SPAs) with rich user interfaces.


While Java applets played a significant role in the early days of interactive web content, their use has largely been superseded by more modern, secure, and efficient web technologies. The legacy of applets lives on in the push towards rich, dynamic web experiences, but developers and website designers now have a broader, more robust set of tools to achieve these goals without the drawbacks associated with applets.

See Also

An Applet is a small application designed to run within a larger application or on a web page. Initially popularized in the early days of the internet, applets were commonly used to provide interactive features to web pages that could not be achieved with HTML alone. Java applets, for example, could run within a Java-enabled browser using the Java Virtual Machine (JVM), offering rich user interfaces and complex functionalities ranging from games and calculators to graphing applications. To gain a comprehensive understanding of applets, their development, usage, and the broader context of web development and software engineering, exploring the following topics is highly beneficial:

  • Java Programming Language: Understanding the basics of Java, the primary language used for developing applets, including its syntax, core libraries, and object-oriented programming principles.
  • Web Development Fundamentals: Covers the foundational knowledge of web development, including HTML, CSS, and JavaScript, essential for integrating applets into web pages.
  • Java Virtual Machine (JVM): Discusses the architecture and functioning of the JVM, which is crucial for running Java applets and standalone Java applications across different platforms.
  • Client Server Architecture: Explores the architectural model of client-server computing, which is fundamental to understanding how applets interact with web servers and databases to fetch and display data dynamically.
  • Browser Plugins and Extensions: Covers the role and functionality of browser plugins and extensions, including how Java applets require a Java plugin to run within a web browser.
  • Security in Web Applications: Discusses security concerns related to running applets, including sandboxing, permissions, and the security model of the Java platform to protect against malicious code.
  • Deprecated Technologies and Modern Alternatives: Explores the transition from legacy web technologies, such as applets, to modern web development practices and frameworks, including HTML5, CSS3, and JavaScript libraries like React and Angular.
  • Cross-Platform Development: Discusses strategies and tools for developing applications that can run across multiple platforms and devices, including the role of Java in facilitating cross-platform compatibility.
  • Software Development Life Cycle (SDLC) Management: Covers the processes involved in the planning, development, testing, deployment, and maintenance of software applications, including applets.
  • User Interface Design (UI): Explores principles of designing effective and intuitive user interfaces for web and software applications, including considerations for usability and accessibility.
  • Networking and Data Communication: Discusses the basics of networking and data communication, essential for understanding how applets communicate with servers and other network resources.
  • APIs and Web Services: Covers the use of APIs and web services for enabling applets and other web applications to interact with external data sources, services, and applications.
  • Emerging Web Technologies: Highlights new and emerging technologies in web development that offer enhanced functionalities and user experiences, providing alternatives to traditional applets.

Exploring these topics provides a comprehensive view of applets within the broader context of web development and software engineering. It highlights the evolution of web technologies, the shift towards modern web development frameworks, and the ongoing importance of understanding fundamental programming and web development concepts.