1. How web server handles multiple requests for same action class(Struts) concurrently?

Struts or any webserver makes new thread for each new
request. so multiple request is served with new request object.

2. Suppose when we are starting startup.bat file of Tomcat server it is not started. DOS window appears for a Second only. What we need do?

Your set up might have been not done well.
Make sure you have added tomcat root directory path in the
CATALINA_HOME environment variable and added the bin path in
the path variable.

3. What is the difference between Tomcat 4.1 and Tomcat 5.0?

Web server (for development) that supports servlets 2.3 and
JSP 1.2 (Tomcat 4) or servlets 2.4 and JSP 2.0 (Tomcat 5).

4. Purpose of NAT Protocol is?

It is used to hide private ip address from public ip
address and provide certain level of security to

5. MAC stands for?

MAC stands for Medium Access Control.

6. What is the output of select * from tab?

it displays the default tables in database

7. What is tomcat? Can we deploy a servelet in tomcat?

Tomcat is a webserver, Which is support 3 -tier

Yes we can

in web.xml

8. What is different between webserver and application server?

The basic difference between a web server and an
application server is
Webserver can execute only web applications i,e servlets
and JSPs and has only a single container known as Web
container which is used to interpret/execute web
Application server can execute Enterprise application, i,e
(servlets, jsps, and EJBs) it is having two containers 1.
Web Container(for interpreting/executing servlets and jsps)
2. EJB container(for executing EJBs). it can perform
operations like load balancing , transaction demarcation
etc etc

9. What is webserver? why it is used?

Transaction with HTTP request and HTTP response is called
Using the internet listening the HTTP request and providing
the HTTP response is also called webserver.It gives only
html output.It will not process business logic .They can
provide Http server.They are static.