JavaBeans basics: Which of the following statements correctly describe a standard JavaBean used in enterprise Java (intended for property introspection and tool support)? Choose the best answer.

Introduction / Context:
The JavaBeans pattern defines conventions that enable frameworks, IDEs, and libraries to discover properties via reflection and to serialize/deserialize objects in a predictable way. Recognizing these conventions is fundamental in JSP/Servlet, Spring, and many Java UI toolkits.

Given Data / Assumptions:

• A “JavaBean” here refers to the classic beans specification (not necessarily EJBs).
• Beans expose properties through accessor (getter) and mutator (setter) methods.
• Tooling often expects a public no-argument constructor for instantiation.

Concept / Approach:

Core JavaBeans conventions include private fields, public getters and setters, and a public no-arg constructor. While a bean must provide a no-arg constructor, it can also define additional overloaded constructors when appropriate. Exposing public instance variables breaks encapsulation and undermines property introspection, so beans rely on methods like getName/setName rather than public fields. Therefore, statements A, B, and C together reflect JavaBeans practice, making “All of the above” correct in this context.

Step-by-Step Solution:

Verification / Alternative check:

Check typical bean classes in frameworks: they include a no-arg constructor, private fields, and get/set pairs; many also provide convenience constructors for initialization.

Why Other Options Are Wrong:

Each individual statement is correct but incomplete by itself; only the combined “All of the above” reflects the complete view expected of JavaBeans.

Common Pitfalls:

Confusing JavaBeans with Enterprise JavaBeans (EJBs); exposing public fields and breaking encapsulation; forgetting the mandatory no-arg constructor required by many tools.

Final Answer:

All of the above are true of a Java bean.