program to assign two integer.....
class A1_xy
{
public static void main(String a[])
{
 int x=10,y=20;
 if ( x > y )
 {
 System.out.println("x is greater y");
 }
 else
 {
 System.out.println("x is not greater than y");
 }
}
}

program to list the factorial.....
class A2_fact
{
public static void main(String a[])
{
 int i=1,n=10,fact=1; 
 while ( i<=n )
 {
 fact=fact*i;
 System.out.println("factorial of"+i+"="+fact);
 i++;
 }
}
}

circumference.....
import java.io.*;
import java.util.*;
class A3_circle
{
public static void main(String a[])
{
 float pi=3.142f,area,cir;
 Scanner sc=new Scanner(System.in);
 System.out.println("Enter radius of a circle:");
 int r=sc.nextInt();
 area = pi*r*r;
 cir = 2*pi*r;
 System.out.println("Area of circle="+area);
 System.out.println("Circumference of a circle="+cir);
}
}

two integers and two float number.....
class A4_overload
{
int x=100,y=200;
public static void main(String ar[])
{
 A4_overload obj=new A4_overload();
 obj.add();
 System.out.println("Sum of integers="+obj.add(10,20));
 System.out.println("Sum of float numbers="+obj.add(10.5f,20.3f));
 }
void add()
{
 int sum=x+y;
 System.out.println("Sum of default values="+sum);
} 
int add(int x,int y)
{ 
 return (x+y);
}
float add(float x,float y)
{
 return (x+y);
}
}

program to mathematical operator...
classAddSub
{
intx=6,y=2;i
nt sum()
{
return(x+y);
}
int sub()
{
return(x-y);
}
}
classMulDivextendsAddSub
{
intmul()
{
return(x*y);
}
int div()
{
return(x/y);
}
}
class mathop
{
publicstaticvoid main(Stringa[])
{
MulDiv obj=new 
MulDiv();System.out.println("Sum="+obj.sum());S
ystem.out.println("Subtraction="+obj.sub());Syste
m.out.println("Multiplication="+obj.mul());System.
out.println("Division="+obj.div());
}
}

Program with class variable that is available for all instances of a class...
class A6_static
{
int x;
static int y,z;
static void mul()
{
 //x=10; // ‘x’ can not be accessed here because it is non-static.
 y=5;
z=15;
int m=y*z;
System.out.println("Multiplication of y & z="+m);
}
public static void main(String ar[]) 
{
 A6_static s1=new A6_static();
 A6_static s2=new A6_static();
 s1.x=10;
 s2.x=20;
 s1.y=100;
 s2.y=200;
 System.out.println("s1's x="+s1.x);
 System.out.println("s2's x="+s2.x);
 System.out.println("s1's y="+s1.y); 
 System.out.println("s2's y="+s2.y);
 A6_static.mul(); 
}
}

Program to create a student class with following attributes; Enrollment No...
import java.util.*;;
public class A7_student
{
 static int eno;
 static String name;
 static float m1,m2,m3,tot;
 static void input()
 {
 Scanner sc=new Scanner(System.in); 
 System.out.println("Enter student enrollment no:");
 eno=sc.nextInt();
 System.out.println("Enter student name:");
 name=sc.next();
 System.out.println("Enter subject1 marks:");
 m1=sc.nextFloat();
 System.out.println("Enter subject2 marks:");
 m2=sc.nextFloat();
 System.out.println("Enter subject3 marks:");
 m3=sc.nextFloat();
 }
 A7_student(float x,float y,float z)
 {
 if(x>=50 && y>=50 && z>=50)
 { 
 tot=x+y+z;
 }
 else
 {
 tot=0;
 }
 }
 void display()
 {
 System.out.println("enrollment no is:"+eno);
 System.out.println("Name is:"+name);
 System.out.println("Marks1="+m1);
 System.out.println("Marks2="+m2);
 System.out.println("Marks3="+m3);
 System.out.println("Total="+tot);
 }
 public static void main(String a[])
{
 A7_student[] obj=new A7_student[3];
 for(int i=0;i<3;i++)
 { 
 A7_student.input();
 obj[i]=new A7_student(m1,m2,m3); 
 obj[i].display(); 
 } 
 }
}

program to demonstrate multiple inheritance....
import java.io.*;
interface circle
{
float pi= 3.142f ;
float compute ( float r );
}
class rect
{
float compute ( float l, float b )
{
return ( l * b ) ;
}
}
class area extends rect implements circle
{
public float compute ( float r )
{
return ( pi * r * r );
}
}
class A8_multipleI
{
public static void main(String args[])
{
area a = new area ();
System.out.println ( "Area of circle=" + a.compute ( 1f ) );
System.out.println ( "Area of rectangle=" + a.compute ( 5f, 10f ) );
}
}

Illustrate creation of thread by...
import java.io.*;
class A extends Thread 
{
public void run ()
{
System.out.println ( "thread A is running" ) ;
}
}
class A9_a_tthread
{
public static void main ( String args[] )
{
A obj = new A ();
obj.start () ;
}
}


import java.io.*;
class A implements Runnable
{
public void run ()
{
System.out.println ( "thread A is running" ) ;
}
}
class A9_b_Rthread
{
public static void main ( String args[] )
{
 A obj = new A () ;
 Thread t = new Thread ( obj ) ;
 t.start () ;
}
}

 Create a package “BCA”....
 package BCA;
public class A11_student
{
 String name,gender;
 int age;
 public A11_student(String n,int a,String g)
 {
 name=n;
 age=a;
 gender=g;
 }
 public void display()
 {
 System.out.println("Name is:"+name);
 System.out.println("Age is:"+age);
 System.out.println("Gender is:"+gender);
 }
}
b. Import above package and access the member variables and function contained in a
package.
import BCA.*;
class A11_pkg
{
public static void main(String ar[])
{
 A11_student obj=new A11_student("abc",20,"f");
 obj.display();
}
}

Program to catch Negative Array Size Exception...
class B1_array
{
public static void main(String ar[])
{
 try
 {
 int a[]=new int[-2];
 System.out.println("Exception not caught because array size is not negative");
 }
 catch(NegativeArraySizeException e)
 {
 System.out.println("Exception Caught \n because Array size is initialized to Negative value");
 }
}
}

Program to create 4×4 grid ....
import java.awt.*;
import java.awt.event.*;
public class B5_grid
{ 
Frame f;
B5_grid()
{
 f=new Frame("Grid with Buttons"); 
 Button b1=new Button("1");
 Button b2=new Button("2");
 Button b3=new Button("3");
 Button b4=new Button("4");
 Button b5=new Button("5");
 Button b6=new Button("6");
 Button b7=new Button("7");
 Button b8=new Button("8");
 Button b9=new Button("9");
 Button b10=new Button("10");
 Button b11=new Button("11");
 Button b12=new Button("12");
 Button b13=new Button("13");
 Button b14=new Button("14");
 Button b15=new Button("15");
 f.add(b1);
 f.add(b2);
 f.add(b3);
 f.add(b4);
 f.add(b5);
 f.add(b6);
 f.add(b7);
 f.add(b8);
 f.add(b9);
 f.add(b10);
 f.add(b11);
 f.add(b12);
 f.add(b13);
 f.add(b14);
 f.add(b15);
 f.setLayout(new GridLayout(4,4));
 f.setSize(400,300); // void setSize(width, height)
 f.setVisible(true);
}
public void windowClosing(WindowEvent we)
{
 f.setVisible(false);
}
public static void main(String ar[])
{
 new B5_grid();
}
}

frame with two buttons father and mother....
import java.awt.*;
import java.awt.event.*;
public class B6_button1 implements ActionListener
{
Frame f;
Button b1 = new Button("Father");
Button b2 = new Button("Mother");
TextField t;
B6_button1()
{
 f=new Frame();
 f.setVisible(true);
 b1=new Button("Father");
 b1.setSize(800,900);
 b2=new Button("Mother");
 b2.setSize(150,150);
 t=new TextField();
 t.setSize(500,100);
 b1.addActionListener(this);
 b2.addActionListener(this);
 f.setSize(500,200);
 f.setLayout(new GridLayout(3,1));
 f.add(t); 
 f.add(b1); 
 f.add(b2);
}
public void actionPerformed(ActionEvent e)
{
 if(e.getSource()==b1)
 {
 t.setText("Father Name is: ABC Father age is: 50"+ "\n" + "Father Designation 
is: BusinessMan");
 }
 else if(e.getSource()==b2)
 {
 t.setText("Mother Name is: XYZ Mother age is: 45 Mother Designation is: Bank 
Employee");
 }
}
public static void main(String ar[])
{
 new B6_button1();
}
}

frame which displays your personal details ....
import java.awt.*;
import java.awt.event.*;
public class B7_person implements ActionListener
{
Frame f;
Button b;
TextField t;
B7_person()
{
 f=new Frame();
 b=new Button("Click");
 t=new TextField();
 f.setSize(300,500);
 f.setVisible(true);
 f.add(t);
 f.add(b);
 f.setLayout(new GridLayout(2,1));
 b.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
 t.setText("Name: Khushi Degree: BCA");
}
public static void main(String ar[])
{
 new B7_person();
}
}

create a window with TextFields and Buttons....import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class B8_add extends Applet implements ActionListener
{
TextField t1,t2,t3;
Label l1,l2,l3;
Button b1,b2;
public void init()
{
 t1=new TextField(20);
 t2=new TextField(20);
 t3=new TextField(20);
 l1=new Label("A");
 l2=new Label("B");
 l3=new Label("A + B");
 b1=new Button("Add");
 b2=new Button("Clear");
 add(l1);
 add(t1);
 add(l2);
 add(t2);
 add(l3);
 add(t3);
 add(b1);
 add(b2);
 b1.addActionListener(this);
 b2.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
 int a,b,sum;
 if(e.getSource()==b1)
 {
 a=Integer.parseInt(t1.getText());
 b=Integer.parseInt(t2.getText());
 sum = a+b;
 t3.setText(Integer.toString(sum));
 }
 else if(e.getSource()==b2)
 {
 t1.setText(" ");
 t2.setText(" ");
 t3.setText(" ");
 }
}
}

good morning good afternoon good ...
import java.awt.*;
import java.awt.event.*;
public class B9 extends Frame implements KeyListener
{
TextField t;
public B9()
{
Frame f=new Frame("Key board Events");
t=new TextField();
f.add(t);
f.setSize(400,300);
f.setVisible(true);
f.setLayout(null);
t.addKeyListener(this);
}
public void keyTyped(KeyEvent ke)
{
 if(ke.getKeyChar()=='M' || ke.getKeyChar()=='m')
 {
 t.setText("Good Morning");
 }
 else if(ke.getKeyChar()=='A' || ke.getKeyChar()=='a')
 {
 t.setText("Good AfterNoon");
 }
 else if(ke.getKeyChar()=='E' || ke.getKeyChar()=='e')
 {
 t.setText("Good Evening");
 }
 else if(ke.getKeyChar()=='N' || ke.getKeyChar()=='n')
 {
 t.setText("Good Night");
 }
 else
 {
 t.setText(" ");
 }
}
public void keyReleased(KeyEvent ke)
{
}
public void keyPressed(KeyEvent ke)
{
}
public static void main(String ar[])
{
 new B9();
}
}

 various mouse handling events....
 import java.awt.*;
import java.awt.event.*;
public class B10_me extends Frame
{
 public B10_me()
 {
 // adding MouseAdapter to frame
 mouse_events ph = new mouse_events();
 addMouseListener(ph);
 addMouseMotionListener(ph);
 setSize(300, 300);
 setVisible(true);
 }
 public static void main(String args[])
{
 new B10_me();
 }
}
class mouse_events extends MouseAdapter // second class 
{
 public void mouseClicked(MouseEvent e)
 {
 System.out.println("You clicked mouse at coordinates " + e.getX() + ", " + e.getY());
 }
 public void mouseReleased(MouseEvent e)
 {
 System.out.println("Mouse released");
 } 
 public void mouseEntered(MouseEvent e)
 {
 System.out.println("mouse entered");
 }
 public void mouseExited(MouseEvent e)
 {
 System.out.println("mouse exited");
 }
 public void mousePressed(MouseEvent e)
 {
 System.out.println("mouse pressed at:"+e.getX());
 }
 public void mouseDragged(MouseEvent e)
 {
 System.out.println("dragging mouse at :"+e.getX()+" , "+e.getY());
 }
 public void mouseMoved(MouseEvent e)
 {
 System.out.println("Mouse moved at:"+e.getX() + " , " + e.getY());
 }
}

 create menubar and pull-down menus...
 import java.awt.*;
import java.awt.event.*;
class B11_menu extends WindowAdapter
{
Frame f;
B11_menu()
{
 f=new Frame("Menu & DropDown Menu");
 MenuBar mb=new MenuBar();
 Menu m=new Menu("Degree Courses");
 Menu subm=new Menu("Science");
 MenuItem i1=new MenuItem("BCA");
 MenuItem i2=new MenuItem("BBA");
 MenuItem i3=new MenuItem("BCom");
 MenuItem i4=new MenuItem("BSc");
 MenuItem i5=new MenuItem("Msc");
 m.add(i1);
 m.add(i2);
 m.add(i3);
 subm.add(i4);
 subm.add(i5);
 mb.add(m);
 m.add(subm);
 f.setMenuBar(mb);
 f.setSize(200,200);
 f.setVisible(true);
}
public static void main(String ar[])
{
 new B11_menu();
}
}