Java Applets, Servlets and JSP : MCQs & PYQs with Explanation

Option B

A servlet is a Java class that runs inside a servlet container such as Apache Tomcat. The servlet container manages the servlet's lifecycle, including creating the servlet, initializing it, handling requests, and eventually destroying it.
The init() method is called by the servlet container once when the servlet is initialized. It is mainly used to perform initialization tasks, such as reading configuration information or preparing resources required by the servlet.

Option A

In a Java web application using HttpServlet, an HTTP GET request is generally handled by the doGet() method. The servlet container receives the clients GET request and invokes the appropriate servlet method to process it.
HTTP Methods in HttpServlet:
HTTP methods define what type of operation a client wants to perform on a web resource. When a browser or another client sends an HTTP request to a Java servlet, the servlet container identifies the HTTP method and, for an HttpServlet, dispatches the request to the corresponding method such as doGet() or doPost().

• The main servlet methods for handling HTTP requests are defined in the HttpServlet class.
• Therefore, doGet(), doPost(), doPut(), doDelete(), doHead(), doOptions(), and doTrace() all belong to the same HttpServlet class. A servlet class normally extends HttpServlet and overrides the appropriate method according to the type of HTTP request it needs to handle.

HttpServlet belongs to the jakarta.servlet.http package in modern Jakarta Servlet applications. In older Java EE applications, the corresponding package is javax.servlet.http.

Option A

JSP (Java Server Pages) is a server-side web technology used to create dynamic web pages. 
A JSP page does not normally execute directly in the users browser. Instead, the web/servlet container processes the JSP page and translates it into a Java servlet. The servlet is then compiled and executed on the server to generate the response.

Note:
JSP and Servlet are closely related. A Servlet is primarily Java code that handles requests and responses, while JSP provides a page-oriented way to generate dynamic web content. Internally, the container uses a servlet representation to execute a JSP.
 

Option B

In JSP (Java Server Pages) technology, JSP pages are first translated into Java servlets. These servlets are then compiled and executed by the web server. This allows JSP to create dynamic and interactive web pages.
<%@ page language="java" %>
<html>
<body>
    <h1>Hello, JSP Example</h1>
    <%
        String name = "Suresh";
        out.println("Welcome, " + name);
    %>
</body>
</html>

When you save this file as myfile.jsp and run it on a server like Tomcat, the server automatically converts it into a servlet like this:
public final class myfile_jsp extends HttpJspBase {
    public void _jspService(HttpServletRequest request,
                            HttpServletResponse response)
                     throws IOException, ServletException {
        response.setContentType("text/html");
        JspWriter out = response.getWriter();
        out.write("<html><body>");
        out.write("<h1>Hello, JSP!</h1>");
        String name = "Suresh";
        out.write("Welcome, " + name);
        out.write("</body></html>");
    }
}

Option C

In JSP (Java Server Pages), understanding how variables behave across multiple requests is essential. JSP provides different scripting elements such as declarations <%! %>, scriptlets <% %>, and expressions <%= %>, each with a specific role and scope.
Declarations <%! %>

• Variables declared inside <%! %> are instance variables of the JSP servlet.
• They are initialized once when the JSP servlet is loaded and retain their values between requests.

Scriptlets <% %>

• Code inside <% %> runs every time the JSP page is requested.
• Here, val++ increments the value of val on each request.

• Since val is declared in <%! %> (declaration), it retains its value across multiple accesses.

Option D

JSP provides different mechanisms for including or transferring control to another resource. The <jsp:include> action is used to include the output of another resource at request time. The included resource may be another JSP page, servlet, or other resource that can process the request.
E.g.:
<jsp:include page="header.jsp" />
When this JSP page is requested, the container processes header.jsp and includes its output in the current response.

The <jsp:include> vs Include Directive:

Option B

A Java Applet is a small Java program designed to be embedded in another application or environment, historically most commonly a web page. Unlike a normal Java application, an applet does not normally contain a main() method as its entry point. Its execution is controlled by the applet environment.
E.g.:
import java.applet.Applet;
import java.awt.Graphics;
public class Example extends Applet
{
    public void paint(Graphics g)
    {
        g.drawString("Suraku Academy", 75, 75);
    }
}
Java applets are now a legacy technology and are no longer supported by modern web browsers.

Option D

In Java, the drawString() method is used to display a string of text at a specified position when working with graphics. It is defined in the Graphics class, which belongs to the java.awt package.
E.g.:
import java.awt.Graphics;
class Example
{
    public void paint(Graphics g)
    {
        g.drawString("Banjara Nirmohi", 50, 50);
    }
}
Here, g is an object of the Graphics class, and drawString() displays " Banjara Nirmohi" at the specified (x, y) position.

Option A

In a Java applet, setBackground() changes the background color, but the visual change may not appear immediately on the screen. To request the applet to be redrawn, the repaint() method is called.
E.g.:
import java.applet.Applet;
import java.awt.Color;
public class Example extends Applet
{
    public void changeColor()
    {
        setBackground(Color.GREEN);
        repaint();
    }
}

Option A

A Java applet is a small Java program designed to be embedded in an HTML document and executed within a Java-enabled web browser or applet environment. Applets were mainly used to provide interactive features on web pages.
For example, an applet could be used to display a simple animation, graphical object, or interactive component inside a web page.
A traditional Java applet is a small Java program that extends the Applet class and uses lifecycle methods such as init(), start(), stop(), and destroy().

E.g.:
import java.applet.Applet;
import java.awt.Graphics;
public class MyApplet extends Applet
{
    public void paint(Graphics g)
    {
        g.drawString("Suraku Academy", 50, 50);
    }
}
HTML Code:
<html>
<body>
  <applet code="MyApplet.class" width="300" height="200">
</applet>
</body>
</html>