In the Servlet 2.4 specification SingleThreadModel has been deprecated, why? | Java JSP

Because it is not practical to have such model. Whether you set isThreadSafe to true or false, you should take care of concurrent client requests to the JSP page by synchronizing access to any shared objects defined at the page level.

How many JSP scripting elements are there and what are they? | Java JSP

There are three scripting language elements: declarations, scriptlets, expressions.

How to Retrieve Warnings? | Java JSP

SQLWarning objects are a subclass of SQLException that deal with database access warnings. Warnings do not stop the execution of an application, as exceptions do; they simply alert the user that something did not happen as planned. A warning can be reported on a Connection object, a Statement object (including PreparedStatement and CallableStatement objects), or a ResultSet object. Each of these classes has a getWarnings method, which you must invoke in order to see the first warning reported on the calling object
SQLWarning warning = stmt.getWarnings();
if (warning != null)
{
while (warning != null)
{
System.out.println("Message: " + warning.getMessage());
System.out.println("SQLState: " + warning.getSQLState());
System.out.print("Vendor error code: ");
System.out.println(warning.getErrorCode());
warning = warning.getNextWarning();
}
}

How many messaging models do JMS provide for and what are they? | Java JSP

JMS provide for two messaging models, publish-and-subscribe and point-to-point queuing.

What are the two kinds of comments in JSP and what's the difference between them? | Java JSP

<%-- JSP Comment --%>

What is a JSP and what is it used for? | Java JSP

Java Server Pages (JSP) is a platform independent presentation layer technology that comes with SUN s J2EE platform. JSPs are normal HTML pages with Java code pieces embedded in them. JSP pages are saved to *.jsp files. A JSP compiler is used in the background to generate a Servlet from the JSP page.

What are the Object and Class classes used for? | Java JSP

The Object class is the highest-level class in the Java class hierarchy. The Class class is used to represent the classes and interfaces that are loaded by a Java program.