Question

State whether each of the following is true or false. If false, explain why. a) Every JSP web page created in Java Studio Creator 2 has its own Application Bean, SessionBean, and Request Bean files. b) Event-processing life-cycle method init is invoked every time a page loads. c) Every component on a JSP web page is bound to a property in the Java page bean file. d) A single JSF component may have multiple validation components placed on it. e) If no expiration date is set for a cookie, that cookie will be destroyed at the end of the browser session. f) Each JSF component maps to exactly one corresponding XHTML element. g) Expressions in the JSF Expression Language syntax are delimited by . h) The SessionBean can store only primitive properties and properties of type String.

Short answer

False, False, True, True, True, False, False, False.

Step-by-step solution

Evaluate statement (a)

The statement (a) is false. Not every JSP web page created in Java Studio Creator 2 inherently has its own Application, Session, and Request Bean files. They are not generated automatically for each page. These elements can be used as needed, but they are not a requirement for each page.

Evaluate statement (b)

The statement (b) is false. The `init` method is invoked when a page is first instantiated and not every time the page loads. It is typically used to perform one-time setup tasks when the page is first accessed.

Evaluate statement (c)

The statement (c) is true. JSP components, such as input fields, can be bound to properties in a managed bean, also known as a backing bean, allowing them to interact with Java code.

Evaluate statement (d)

The statement (d) is true. A JSF component can have multiple validator tags, allowing the component to be validated in different ways.

Evaluate statement (e)

The statement (e) is true. If a cookie does not have an expiration date set, it is considered a session cookie, which is deleted when the browser session ends.

Evaluate statement (f)

The statement (f) is false. A JSF component may not map to a single XHTML element as JSF components can represent more complex constructs that may render as multiple XHTML elements.

Evaluate statement (g)

The statement (g) is false. Expressions in the JSF Expression Language are delimited by curly braces \(\{ \}\) combined with a pound sign (\(\#\)), not HTML comment tags \(\\).

Evaluate statement (h)

The statement (h) is false. The SessionBean can store complex Java objects, not just primitive types and Strings. It can manage beans of various data types, including collections and user-defined objects.

Key concepts

Java Studio Creator

Java Studio Creator, a notable development tool by Sun Microsystems, simplifies the creation of Java Server Pages (JSP) and JavaServer Faces (JSF) applications. Often used in educational settings, it offers tools that streamline web application development. However, it's important to understand some misconceptions associated with it.

Not every JSP page created within Java Studio Creator is automatically equipped with its own Application, Session, and Request Bean files. Instead, these files are part of a broader bean management framework and are not automatically generated for each page. Beans are essential in managing state and encapsulating business logic, but their creation depends on the requirements of the application.

To make the most of Java Studio Creator, developers should focus on understanding how beans can be manually created and managed as needed.

Event-Processing Life-Cycle

Understanding the JSF event-processing life-cycle is crucial for managing how applications respond to user inputs and other events. The life-cycle consists of a series of phases that process and render a JSF page.

The `init` method, specifically, plays a role in this life-cycle. However, contrary to some beliefs, the `init` method is not called every time a page loads. It is invoked only once, when a page is first instantiated, to perform initial setup tasks. This distinction helps developers avoid unnecessary re-execution of certain setup code each time a page is loaded.

Proper event management in JSF applications is key to ensuring efficient loading and user interaction, and understanding the life-cycle assists in efficiently managing application states.

JSF Validation Components

JSF validation components are integral to maintaining data integrity in web forms. They ensure that the information submitted meets specific criteria before being processed.

A single JSF component can indeed support multiple validation components. This feature allows developers to enforce multiple rules simultaneously, such as checking that an email field contains a valid address and ensuring its input length is within specified bounds.

Utilizing multiple validators on a component enhances security and data accuracy, providing a robust mechanism to guard against invalid inputs and enhance user experience.

Session Cookies

Session cookies are temporary cookies that play a key role in maintaining a user session as they navigate a web application. These cookies store session-specific data without an expiration date, making them essential for managing short-term user interactions.

If no expiration date is set for a cookie, it is classified as a session cookie and gets deleted once the browser session ends. Their existence is limited to the duration of a single session, helping maintain privacy while providing essential functionality in shared browsing environments.

JSF Expression Language

The JavaServer Faces (JSF) Expression Language (EL) is a powerful feature that eases communication between the UI components and their backing beans. EL expressions facilitate dynamic value binding and method invocation.

Expressions in JSF EL are not enclosed in HTML comment tags \`\`. Instead, they use a distinctive syntax: curly braces \(\{\}\) combined with a pound sign (\(\#\)), such as \(\#{bean.property}\). This syntax allows the EL to evaluate Java expressions and integrate seamlessly with the application logic.

Understanding and correctly using this syntax is crucial for linking UI components to data and methods, thus enabling effective interaction in JSF applications.