what happens when you type a url in the browser. what is dns?

write some program to do sorting of a given array. i prefered bubble sort(only that i came to remember)

what is relative path? write a program to convert relative path to absolute path.

write a program to reverse the order of the given single linked list.

Add comment to all java files in a directory and its sub directories.

what could be the reason when a website doesn't open.

7. Implementation of singleton class (java).

ONE WAY:
public class Singleton {
   protected Singleton() {}
   static private Singleton _instance = null;
   static public Singleton instance() {
      if(null == _instance) {
         _instance = new Singleton();
      }
      return _instance;
   }
}

ANOTHER WAY:
public class Singleton {
  private static final Singleton INSTANCE = new Singleton();
  private Singleton() {}
  public static Singleton getInstance() { return INSTANCE; }
}

8. There is a file with information of student. The file is comma separated and the contents are in the order of 'Name, class, age, total'. write a script to get the the students whose total is more than some number(400).
The command will be like this:
cat student.txt | awk '{if( $3 >= 23){ printf $0; }}'

9. Basic unix commands like, wc, who, find, diff between find and locate, du and df etc.
10. Delete a given number from a singly linked list. given linked list is 1->2->3->4->5. start node of the list and the number to be deleted also given.write a script to delete the number 3 and have been asked to do a test run.
11. write a perl script to get home page of http://rediff.com and stire it to a location. write a shell script to find all the links( anchors) inside the file and get all its contents.
12. what is your achievement in past experience.
13. SQL: you have two tables(student and mark ) student table has student_id, student_name, class and mark table has student_id, subject_name, mark_obtained. mark table will have multiple records for a student(all subjects). write a query to find name of the student who maximum mark.
14. write a program to find factorial(concept of recursion)
15. what is the use of multi threading?where we cant use this.
16. did you solve any problem when the project was in live?
17. A server is running with 100% cpu utilization. write a script to kill the top 5 processes? write a script to run it for every 5 minutes?(don't use crontab). Use sleep method.

I hope this will be helpful to you.
Please let me know if you have any clarifications.