In computing, what is an "applet" most commonly understood to be?

Introduction / Context:
When Java became popular on the web, a special type of small program called an applet was widely used to add interactivity to web pages. Although browser support for applets is now rare, the term still appears in many exam questions and computer awareness materials. Understanding what an applet is in this historical and technical context is important for general knowledge about programming and web technologies.

Given Data / Assumptions:

• The question refers to the term applet in computing.
• We assume the classic Java based meaning, not informal uses of the word.
• Options discuss a Java application, a virus, a firewall, and a cookie like object.
• The focus is on the most common and accepted definition in programming.

Concept / Approach:
An applet is traditionally defined as a small application written in Java that is designed to be run inside another program, usually a web browser or a special applet viewer. It is not a stand alone desktop application; instead, it is embedded in an HTML page using specific tags. The browser then uses a Java plug in or virtual machine to execute the applet code inside a restricted environment or sandbox. This is very different from a virus, firewall, or cookie. Therefore, the correct answer must explicitly mention a small Java program running inside another application.

Step-by-Step Solution:
Step 1: Recall that applets were introduced as a way to bring Java code to web pages, providing interactive content.Step 2: Understand that applets run under the control of the Java Virtual Machine inside the browser, not as separate programs with full system access.Step 3: Note that the term firewall refers to security hardware or software that filters network traffic and is unrelated to Java applets.Step 4: Remember that cookies are small text files stored by the browser, not executable programs.Step 5: Conclude that an applet is best described as a small Java program that runs inside a web browser or applet viewer.

Verification / Alternative check:
Java documentation describes java.applet.Applet as a special class that programmers extend when building applets. The description emphasises that applets are small applications that require a host environment such as a browser. Security restrictions are also highlighted, reinforcing that applets are different from full scale Java applications. This official documentation aligns exactly with the selected option and not with any of the other choices.

Why Other Options Are Wrong:
A computer virus is malicious software that spreads and damages data; applets are not inherently malicious and are used for legitimate purposes. A firewall is a network security system, not a type of Java program. Cookies store preferences and session information as data, not executable code. None of these match the technical meaning of applet in the Java ecosystem.

Common Pitfalls:
Some learners confuse the term applet with general applications or mobile apps, particularly because the words sound similar. Others associate any small program on the Internet with viruses due to security fears. It is important to separate the specific Java meaning of applet from these broader or informal uses. For exam questions, always relate applet to a small Java program embedded in a browser.

Final Answer:
The correct answer is A small Java program that runs inside a web browser or applet viewer, which captures the traditional and widely accepted definition of an applet in computing.