Important Basic Facts about Java
1. Multiple Inheritance can be achieved with the help of interfaces as they don’t implement any function just give a guidelines for the implementation.
E.g.
interface S{final int a=0;}
interface A extends S{}
interface B extends S{}
interface C extends B,A{
}
class Multiple implements C
{
public static void main(String args[])
{
System.out.println(a);
}
}
Output: 0
2. Parent class always passes its own function to the child with its definition in inheritance. So while re-implementation of any interface already implemented by the parent does not make any compulsion for the child class.
E.g.
interface S{final int a=0; void fun();}
interface A{void fun1();}
interface B extends S,A{void fun2();}
abstract class Abst implements B
{
public void fun(){System.out.println("Abtract");}
}
class last extends Abst implements S
{
public void fun1(){System.out.println("lastfun1");}
public void fun2(){System.out.println("lastfun2");}
}
class MultImp{
public static void main(String args[])
{
last l =new last();
l.fun();l.fun1();l.fun2();
}
}
Output:
Abtract
lastfun1
lastfun2
3. Multiple Inheritance in no way can be implemented in Classes
4. All the functions in Java are virtual by default so always support Run Time Polymorphism.
5. Anonymous Inner Class Advantage: It reduces the code size, and also does not create a separate class file for adapter. Disadvantage: It cannot be reused if required at the later stage.
6. Threads can be created using two methods:
a. Implements Runnable Interface: need object of Thread class
b. Extends Thread Class: The object of extended class itself act as a new Thread.
7. MenuBar have Menus which can have Menuitem, CheckboxMenuItem as well as Menu (which act as submenu).
8. Update is called in Paint whenever it is required to save the previous content intact.
9. Objects are called by reference and Variables are called by value.
10. Autoboxing : when a basic type is converted into a wrapper type.
11. Unboxing : when a Wrapper type is converted into a basic type.
Internal practical examination
(thursday)
Experiments:
Divisble by 5: CREATE A FRAME MECHANISM TO DEMONSTRATE THE APPEARANCE OF GLOWING SUN AT THE EXACT CENTER OF THE SCREEN. IT SHOULD INCREASE AND DECREASE ITS GLOWNESS PERIODICALLY.
Divisible by 4 & not by 5: CREATE A CONSOLE MECHANISM TO DEMONSTRATE THE WORKING OF TWO SEMAPHORE LOCKS FOR SYNCHRONIZATION. AVOID DEADLOCK.
Divisible by 3 & not by 5 and 4: CREATE AN APPLET APPLICATION TO DEMONSTRATE WORKING OF OPENING SORTING THE LIST OF NAMES SUPPLIED AS PARAMETER FROM HTML DOCUMENT. FOR E.G. 'ABILITY' SHOULD COME BEFORE 'AGILITY'.
Divisible by 2 & not by 5,4 and 3: CREATE A SWING APPLICATION TO OPEN A FILE AND THEN PRINT THE LIST OF ALL THE WORDS REPEATED MORE THEN ONCE IN THE WHOLE FILE.
REST OF ALL: CREATE AN APPLET TO DEMOSTRATE THE DROPPING OF A GLASS BALL FROM A HEIGHT SELECTED BY MOUSE ON TO A FIXED PLATFORM. USE MOUSE EVENTS AND REMEMBER ''IT IS A GLASS BALL''.
Internal practical examination
(monday)
Experiments:
No. 1:
Divisble by 5: CREATE AN APPLET MECHANISM TO DEMONSTRATE THE CALCULATION OF AGE ON SELECTION OF DATE OF BIRTH. USE EVENT HANDLING.
No.2
Divisible by 4 & not by 5: CREATE A FRAME MECHANISM TO DEMONSTRATE THE WORKING OF COUNTDOWN STARTING FROM 1HR:00MIN:00SEC AND SHOULD STOP AT 00:00:00. USE MULTI THREADING.
No.3
Divisible by 3 & not by 5 and 4: CREATE A CONSOLE APPLICATION TO DEMONSTRATE WORKING OF FCFS PROTOCOL FOR P1(6), P2(2), P3(1). USE THREAD WAITING FUNCTIONS.
No.4
Divisible by 2 & not by 5,4 and 3: CREATE AN USERNAME AND PASSWORD ACCEPTANCE FORM & SHOW MESSAGE AS WELCOME OR WRONG USERNAME/PASSWORD MESSAGE ACCORDINGLY. TAKE USERNAME: Admin & PASSWORD: ABC@123 AS VALID.
No.5
REST OF ALL: CREATE A CONSOLE APPLICATION TO COUNT NO. OF WORDS, LINES AND CHARACTERS IN A FILE. THE COUNT FUNCTION HAS TO MADE COMPULSORY FOR THE IMPLEMENTING CLASS. USE INTERFACES.
Practical To be performed as below:
Internal practical examination
(wednesday)
Experiments:
Divisble by 5: CREATE AN APPLET MECHANISM TO DEMONSTRATE THE APPEARANCE OF RANDOM COLOURED DROPS CONTINOUSLY. IT SHOULD RESET TO START FROM BEGINNING ON MOUSE PRESSED.
Divisible by 4 & not by 5: CREATE A FRAME MECHANISM TO DEMONSTRATE THE WORKING OF MOVING SNAKE GAME, THE SNAKE SHOULD CHANGE ITS DIRECTION ON KEYBOARD KEYS. USE KEY EVENTS.
Divisible by 3 & not by 5 and 4: CREATE A APPLET APPLICATION TO DEMONSTRATE WORKING OF OPENING A FRAME CONTAINING THE RESULT OF SEARCH OF A KEYWORD FROM A TEXT AREA INSIDE AN APPLET.
Divisible by 2 & not by 5,4 and 3: CREATE A CONSOLE APPLICATION TO DEMONSTRATE THE WORKING OF SYNCHRONIZED BLOCK BETWEEN TWO THREAD. TRY TO AVOID RACE CONDITION.
REST OF ALL: CREATE A FRAME TO DEMOSTRATE WORKING OF A FORM TO SELECT A DATE IN FORM OF MM DD YY. APPLY A LOGIC TO AVOID WRONG DATE SELECTION. FOR E.G. IF MONTH IS FEB IT SHOUL NOT ALLOW TO SELECT 31 AS DD.
