Difference between include directive, include action and JSTL import tag in JSP? Answer

There are three main ways to include the content of one JSP into another:

include directive

JSP include action

and JSTL import tag

The include directive provides static inclusion. It adds the content of the resource specified by its file attribute, which could be HTML, JSP, or any other resource at translation time.

Any change you make in the file to be included after JSP is translated will not be picked up by the include directive.

Difference between include() and forward() methods of RequestDispatcher in Servlert

What is the difference between include and forward methods of RequestDispatcher interface is one of the frequently asked Servlet questions from Java EE interviews and we'll see how you can answer this question on your interview. You get the RequestDispatcher reference either from ServletContext or ServletRequest interface and even though both include() and forward() method allow a Servlet to interact with another servlet, the main difference between include() and forward is that the include() method is used to load the contents of the specified resource (could be a Servlet, JSP, or static resource like HTML files) directly into the Servlet's response, as if it is part of the calling Servlet. 

Difference between jsp:include and jsp:forward action- Example

JSP provides standard actions to do things without using Java inside the scriptlet. Two of such standard actions, which help JSP to interact with other server resources e.g. another JSP, Servlet, or HTML files are, include and forward actions. The <jsp:forward> action enables you to forward an HTTP request to a static HTML file, a servlet, or another JSP. It has an attribute called page, which accepts the URL of another resource as shown below:

<jsp:forward page="URL" /> 

6 Difference between include directive and include action in JSP

Difference between include directive and include action
Even though both include directive and include action allows you to include the response of one JSP into another, they are quite different from each other e.g. include directive is processed at translation time and used to include the static resources e.g. HTML files, images, and CSS, etc, while the <jsp:include> action is processed at request time and used to include more dynamic resources e.g. JSP or Servlet. What is the difference between include directive and include action is also one of the most popular JSP interview questions, mostly asked either at telephonic round or first few round of Java web developer interviews?

How to create a custom tag in JSP? Steps and Example

You can create a custom tag in JSP either by implementing the SimpleTag interface or extending SimpleTagSupport class. Custom tags are introduced in JSP 2.0 in an effort to minimize Java code from JSP to keep them maintainable and allow page authors to work more in HTML or XML, like environment than writing Java codes. SimpleTag and SimpleTagSupport allow you to create a custom tag in JSP. It's easier to start with SimpleTagSupport class because it implements all methods of the SimpleTagSupport interface and if you are writing a basic tag then you just need to override the doTag() method of this class. 

9 JSP Implicit Objects and When to Use Them

If you are new to JSP then your first question would be what are implicit objects in JSP? Well, implicit objects in JSP are Java object which is created by Servlet containers like the tomcat or Jetty during translation phase of JSP, when JSP is converted to Servlet. These objects are created as local variables inside the service() method generated by the container. The most important thing about the implicit objects is to remember that these objects are available to any JSP developer inside the JSP page and they can do a lot of things with implicit objects and expression language which was only possible with scriptlet earlier. That's why they are known as implicit objects.