Struts Interview Questions and Answers
Ques 36. What about JSTL and JavaServer Faces ?
Ans. JSTL, the JavaServer Standard Tag Library, is a set of JSP tags that are designed to make it easier to develop Web applications. JavaServer Faces (JSF) is a specification for a new technology that promises to make it easier to write MVC applications, both for the Web and for the desktop.
The inventor of Struts, Craig McClanahan, is the specification co-lead for JavaServer Faces (JSR 127), and architect of the reference implemenation as well as Java Studio Creator. Both JSTL and JSF are complementary to Struts.
The mainstay of the Struts framework is the controller components, which can be used with any Java presentation technology. As new technologies become available, it is certain that new "glue" components will also appear to help these technologies work as well with Struts.
Struts originally came bundled with a set of custom JSP tags. Today, several extensions are available to help you use Struts with other popular presentation technologies, like XSLT and Velocity. Likewise, extensions for JSTL and JSF are now available as well.
The JSTL reference implementation is available through the Jakarta Taglibs site. A JSTL taglibs for Struts, Struts-El , is available and distributed with Struts beginning with the 1.1 release.
The JSF specification and reference implementation is available through Sun's The JSF specification and reference implementation is available through Sun's Java ServerFaces page. An early-release JavaServer Faces taglib for Struts, Struts-Faces, is also in early release and available through the nightly build. The Struts Faces taglib is expected to work with any compliant JSF implementation, including MyFaces.
Ques 37. Is there a particularly good IDE to use with StrutsAns. Struts should work well with any development environment that you would like to use, as well as with any programmers editor. The members of the Struts development team each use their own tools such as Emacs, IDEA, Eclipse, and NetBeans.
Ques 38. Why was reload removed from Struts (since 1.1)?Ans.
The problem with ReloadAction was that Struts was trying to act like a container, but it couldn't do a proper job of it. For example, you can't reload classes that have been modified, or (portably) add new classes to a running web application (even if the container supported it).
Meanwhile, as Struts 1.1 was being developed, work progressed on things like Tomcat's reload command via the Manager webapp. This feature allows you to quickly reload-on-demand, complete with saving and restoring your session). It started to make even less sense for Struts to half-implement a feature that containers are implementing fully.
A more minor point is that freezing the configuration information at application startup time allows Struts to safely access the mapping information without bothering with synchronization. The "startup-only" strategy creates a modest but real improvement in performance for all users.
So, ReloadAction is not supported since Struts 1.1 for two reasons:
* It never did let you reload everything that you would really want to -- particularly changed classes -- so many people ended up having to reload the webapp anyway.
* Containers are starting to offer reload-on-demand features which does the same thing as the Struts ReloadAction, only better.
* Not supporting ReloadAction lets Struts avoid doing synchronization locks around all the lookups (like figuring out which action to use, or the destination of an ActionForward) so applications can run a little faster.
Of course, if someone came up with an implementation that solved these problems without creating any others, we would not be opposed to including a new ReloadAction.
Ques 39. What is a modular application? What does module-relative mean?Ans. Since Struts 1.1, the framework supports multiple application modules. All applications have at least one root, or default, module. Like the root directory in a file system, the default application has no name. (Or is named with an empty string, depending your viewpoint.) Developing an application with only a default module is no different from how applications were developed under Struts 1.0. Since Struts 1.1, you can add additional modules to your application, each of which can have their own configuration files, messages resources, and so forth. Each module is developed in the same way as the default module. Applications that were developed as a single module can added to a multiple module application, and modules can promoted to a standalone application without change. For more about configuring your application to support multiple modules, see Configuring Applications in the User Guide.
But to answer the question =:0), a modular application is a Struts application that uses more than one module. Module-relative means that the URI starts at the module level, rather than at the context level, or the absolute-URL level.
* Absolute URL: http://localhost/myApplication/myModule/myAction.do
* context-relative: /myModule/myAction.do
* module-relative: /myAction.do
The Struts Examples application is a modular application that was assembled from several applications that were created independently.
Ques 40. Why are some of the class and element names counter-intuitive?Ans. The framework grew in the telling and, as it evolved, some of the names drifted.
The good thing about a nightly build, is that everything becomes available to the community as soon as it is written. The bad thing about a nightly build is that things like class names get locked down early and then become difficult to change.
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