top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

What is the default value of an object reference declared as an instance variable?

+3 votes
257 views
What is the default value of an object reference declared as an instance variable?
posted Jul 15, 2015 by Karthick.c

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

+1 vote

null unless we define it explicitly.

answer Mar 22, 2016 by Shivam Kumar Pandey
Similar Questions
+2 votes

I declared a variable and incremented/modified it inside Mapper class. Now I need to use the modified value of that variable in Driver class. I declared a static variable inside Mapper class and its modified value works in Driver class when I run the code in Eclipse IDE. But after creating that code as a runable jar from Eclipse and run jar file as “$ hadoop jar filename.jar input output” modified value does not reflect (value is 0) in Driver class.

+2 votes
public class ServletClassName extends HttpServlet {
//declare instance variables for the servlet
int  instanceVar ; // not thread−safe
// overriding the Generic Servlet.init ( )
@Override
public void init ( ) throws ServletException {
// initialize instance variables, etc.
instanceVar = 0 ;
}
. . .
}

Per each page request, in the service() method (which eventually will be either doGet(), doPost(), or whatever),
you can manipulate instance variables.

Write a Servlet that counts the total number of visits (how many times it's being visited from all clients). The Servlet should display the following information

• Total Page Visits:
• Client Remote Address:
• Client Host Address: <client_fully_qualied_url__or__client_IP_address>

The last two can be obtained from the HttpServletRequest, Refer to the Java EE API

then how can re-do these using the Java API for HttpSession.

...