IPT Friday: 25th November 2011

1. Develop an applet to demonstrate the working of a "HIT-ME".

Instead of designing of a hit me, you can take a line or ellipse.

2. Develop a frame to demonstrate the working of pacman.

Just show a moving pacman with closing and opening of mouth.

3. Develop a moving snake game and control it by keyboard.

You just need to move it in a closed boundary.

4. Develop an applet to place a ball wherever you click, if the space been already occupied then ball can not be placed.

5. Create a frame to develop a mechanism to enter hobbies in a text box, on pressing enter the hobby should add in list of your hobbies. Also create a mechanism to remove a wrong entry from the list.

cs

IPT Tuesday: 22nd November 2011

1. Create an applet demo of bouncing ball in the effect of g=9.8m/s2 from a user defined height chosen by the mouse events (use anonymous inner class). In each bounce the height reduction is 20% of original one.

2. Create a demo in which a frame is changing its background continuously in random manner, along with that it is also proving you a functionality to print the series 1+1/2+1/3........n, where n would be entered using text box.

Hint: Use MultiThreading

3. Create a demo in which whenever a character has been entered in to text box it should start searching that keyword from a file and start printing the count in front of the text box.

4. Create a demo to move a ball from a very steep path, the game should get over on touching of any boundaries. Finish only when it reaches finish point without touching any of the boundary.

Use: Mouse Handing Events

IPT Monday: 21st Nov 2011

1. Create an Applet to demonstrate a tic tac toe using mouse events handling, Use Inner Classes.

2. Create a window based program to demonstrate working of psychological answering machine, Use adapter classes. i.e. take one textbox for Q and another read only textbox for answers.

3. Create a multiple ball bouncing game based applet,
Hint: Use Multithreading
Caution: They can collide

4. Create a console based survey of at least 5 Questions to find his interests about technical gadgets.
You need to log his responses in separate files for separate users.
Logging activity should be part of separate user defined package.

There is no call by reference in Java....

The Myth: Primitive types are called by value and Objects are passed by reference in Java.
The Truth: There is no call by reference in Java.
let's see one example:

class Democall
{int ival1=2,ival2=3;
int fun1 (int a, int b) { a=a*2; b=b*2; return(a+b); }

int fun2 (Democall obj) { obj.ival1=obj.ival1*2; obj.ival2=obj.ival2*2; return(obj.ival1+obj.ival2);}

public static void main(String args[])
{
int i=2,j=3;
Democall obj1=new Democall();//new object creation
int k=obj1.fun1(i,j);//passing i,j values to fun1's a,b
System.out.println(i+" "+j+" "+k);
k=obj1.fun2(obj1);//passing value of object obj1 to the fun2's obj
System.out.println(obj1.ival1+" "+obj1.ival2+" "+k);
}
}
output:
2 3 10
4 6 10

Now you might say: yes it is call by reference as second output is indeed changing the values of object.
But the truth lies in the memory operations of java. The function fun1 is totally fine as it is working with primitive types and indeed its is well known as call by value, but in fun2 the obj is itself passed on to the function fun2, so the value of obj1 has to be copied in to obj. Now just think what could be the value of obj1, will it not be the address of the newly created object? So the address of new Democall() is acting as the value for obj1 which would be passed as value to obj, now if obj accesses data member ival1 and ival2 it would be obviously obj1's ival1 and ival2 which ultimately got reflected in main function.
So it will give you a look and feel of a pass by reference but in the actual working it is call by value.

Thanks to IT 3rd Year students...

I thank my all IT 3rd year students for their encouragement and motivation by which i have been able to achieve SCJP 6 ( Oracle JSE 6 Programmer Certified Professional Exam) certification on 30-09-2011. Thanks once again.....

volatile, transient and instanceof in Java...

volatile: a volatile keyword tells the compiler that the variable value can change unexpectedly by other parts of your program. In java sometimes if threads share some variable, for efficiency they all keep their private copy of the shared variable. at certain positions specially in synchronized constructs most updated copy must be referred, so volatile tells the compiler that always use the master copy for volatile variable or keep it as updated as possible.

transient: a transient variable has two objectives in declaration :
1. it must not be serialized
2. it must not persist on storing it in permanent storage area.
i.e. when you store object in hard disk, it would be composed of combination of values of all its data members except transient variable.

instanceof: objectRef instsnceof ClassName return boolean. It is an operator which is used to determine the object with the class name. Its not only match it with its ClassName but even with its parent. However it returns false on null.
E.g. class A{}
class B extends A{}

B objB=new B();
A objA=new A();
B objB1=null;
objB instanceof B//returns true
objB instanceof A//returns true
objA instanceof A//returns true
objA instanceof B//returns false
objB1 instanceof B//returns false
objB1 instanceof A//returns false

Java is not a Purely Object Oriented Language....

As Java is supporting all the features of being Object oriented like inheritence, encapsulation etc. but the primitive types of Java i.e. int, char, bool etc. are not objects which is one of the important condition to be purely object oriented. If still have any query please comment...

For Seminar CSE Students...

If you have any query or suggestions regarding seminar activity, please comment I will try to reply to best of my capabilities....

OS Second term related comments

Some topics regarding second sessional as initiated by ankita
Synchronization
1. All Three basic solutions of synchronization.
2. Bakery Algo.
3. Semaphores- both counting and binary.
4. All Classical problems of synchronization.
5. Critical Regions and monitors.
6. Atomic transactions.
Disc Mgmt
1. All Disc scheduling Algos- remember calculations of distance and memory map.
2. All the latencies and terminology associated with disc working.
3. RAID.
4. Sector sparing and slipping for bad sectors management.
5. Swap space management.
Deadlocks
1. Deadlock conditions.
2. All prevention, avoidance, recovery techniques theory.
3. Do practice safety and resource request, and deadlock detection algos thoroughly with example.
4. How to combine the deadlock approaches.
Device Mgmt
Totally theoretical so nothing can be said about about any one topic.

This is just the my perception about the topics listed here, this is nowhere decrease or increase the importance of any topics which are not listed here, and i personally encourage all the students to read the entire syllabus thoroughly and study all topics very sincerely.
All the best to all.
If any one has any more queries to ask please comment, will try to reply soon.

For OS Students...

Please put up any query of yours regarding OS concepts, mention any suggestion or any thing you would like to share...