Content
1. Simlpe function
public class MethodClass
{
public static void main( String args[ ] )
{
A ob = new A();
ob.displayMsg();
}
}
class A
{
public void displayMsg()
{
System.out.printf( "Welcome to Java\n" );
}
}
Output:
Welcome to Java
2. Program to explain Simple class
class Distance
{
int feet;
double inches;
}
class DistanceDemo
{
public static void main( String args[ ] )
{
Distance d1 = new Distance ();
Distance d2 = new Distance ();
d1.feet = 14;
d1.inches = 9.5;
d2.feet = 19;
d2.inches = 5.5;
System.out.println( "Dist-1 : " + d1.feet + "\'-" + d1.inches + "\"" );
System.out.println( "Dist-2 : " + d2.feet + "\'-" + d2.inches + "\"" );
}
}
Output:
Dist-1 : 14'-9.5"
Dist-2 : 19'-5.5"
3. Program to explain Static or Class Method
public class StaticMethodClass
{
public static void main( String args[ ] )
{
A.displayMsg();
}
}
class A
{
public static void displayMsg()
{
System.out.println( "Welcome to Java" );
}
}
Output:
Welcome to Java
4. Program to explain Setter & Getter method with string variable class
public class SetterGetterClass
{
public static void main( String args[ ] )
{
A ob = new A();
ob.setMessage("friends");
System.out.println(" Welcome to " + ob.getMessage() + " ..!");
}
}
class A
{
private String message;
public void setMessage( String msg )
{
message = msg;
}
public String getMessage()
{
return message;
}
}
Output:
Welcome to friends
5. Program to explain Default Constructor
class Circle
{
private double radius;
Circle()
{
radius = 10.0;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CircleConstructor1
{
public static void main( String args[ ] )
{
Circle c1 = new Circle();
System.out.println(" Area of Circle : " + c1.area());
}
}
Output:
Area of Circle : 314.0
6. Program to explain Parameterized Constructor ( Constructor with arguments ).
class Circle
{
private double radius;
Circle( double rad)
{
radius = rad;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CircleConstructor2
{
public static void main( String args[ ] )
{
Circle c1 = new Circle(10);
System.out.println(" Area of Circle : " + c1.area());
}
}
Output:
Area of Circle : 314.0
7. Program to explain Parameterized Constructor with this reference class
class Circle
{
private double radius;
Circle()
{
radius = 0.0;
}
Circle( double radius)
{
this.radius = radius;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CircleConstructor3
{
public static void main( String args[ ] )
{
Circle c1 = new Circle(10);
System.out.println(" Area of Circle : " + c1.area());
}
}
Output:
Area of Circle : 314.0
8. Program to explain Parameterized Constructor
with Object as Argument with Circle class
class Circle
{
private double radius;
Circle()
{
radius = 0.0;
}
Circle( double radius)
{
this.radius = radius;
}
Circle( Circle ob)
{
radius = ob.radius;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CircleConstructor4
{
public static void main( String args[ ] )
{
Circle c1 = new Circle( 10 );
Circle c2 = new Circle( c1 );
System.out.println(" Area of Circle : " + c2.area());
}
}
Output:
Area of Circle : 314.0
9. Program to explain Calling a Constructor from another Constructor using this
class Circle
{
private double radius;
Circle()
{
this(10);
}
Circle( double radius)
{
this.radius = radius;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CircleConstructor5
{
public static void main( String args[ ] )
{
Circle c1 = new Circle();
System.out.println(" Area of Circle : " + c1.area());
}
}
Output:
Area of Circle : 314.0
10. Program to explain Passing Object to method
class Circle
{
private double radius;
Circle()
{
radius = 0.0;
}
Circle( double radius)
{
this.radius = radius;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CirclePassingObject
{
public static void main( String args[ ] )
{
Circle c1 = new Circle(20);
calcArea( c1 );
}
public static void calcArea( Circle c )
{
System.out.println(" Area of Circle : " + c.area());
}
}
Output:
Area of Circle : 314.0
11. Program to use exit() function
class ExitTest1
{
public static void main( String args[] )
{
System.out.println( "AAA" );
funTest();
System.out.println( "DDD" );
}
public static void funTest()
{
int a = 10;
System.out.println( "BBB" );
if( a == 10 )
System.exit(0);
System.out.println( "CCC" );
}
}
Output:
AAA
BBB
12. Program to use return statement.
class ReturnTest1
{
public static void main( String args[] )
{
System.out.println( "AAA" );
funTest();
System.out.println( "DDD" );
}
public static void funTest()
{
int a = 10;
System.out.println( "BBB" );
if( a == 10 )
return;
System.out.println( "CCC" );
}
}
Output:
AAA
BBB
DDD
13. Program to use instance of operator
class ABC
{
ABC()
{
System.out.println( "Object is created." );
}
}
class XYZ
{
XYZ()
{
System.out.println( "Object is created." );
}
}
public class OpInstanceOf
{
public static void main( String args[ ] )
{
ABC a = new ABC();
if( a instanceof ABC )
{
System.out.println( "a is an instance of class ABC." );
}
else
{
System.out.println( "a is not an instance of class ABC." );
}
if( a instanceof XYZ )
{
System.out.println( "a is an instance of class XYZ." );
}
else
{
System.out.println( "a is not an instance of class XYZ." );
}
}
}
Output:
Object is created.
a is an instance of class ABC.
a is not an instance of class XYZ.
14. Program to use Simple class
class Box
{
double width;
double height;
double depth;
}
class BoxTest1
{
public static void main(String args[ ])
{
Box b1 = new Box();
double vol;
b1.width = 10;
b1.height = 15;
b1.depth = 20;
vol = b1.width * b1.height * b1.depth;
System.out.println("Volume is " + vol);
}
}
Output:
Volume is 3000.0
15. Program to show use of two objects
class Box
{
double width;
double height;
double depth;
}
class BoxTest2
{
public static void main(String args[ ])
{
Box b1 = new Box();
Box b2 = new Box();
double vol;
b1.width = 10;
b1.height = 15;
b1.depth = 20;
b2.width = 5;
b2.height = 6;
b2.depth = 7;
vol = b1.width * b1.height * b1.depth;
System.out.println("Volume is " + vol);
vol = b2.width * b2.height * b2.depth;
System.out.println("Volume is " + vol);
}
}
Output:
Volume is 3000.0
Volume is 210.0
16. Program to explain Function within class through Box class
class Box
{
double width;
double height;
double depth;
void volume()
{
System.out.print("Volume is ");
System.out.println(width * height * depth);
}
}
class BoxTest3
{
public static void main(String args[ ])
{
Box b1 = new Box();
Box b2 = new Box();
double vol;
b1.width = 10;
b1.height = 15;
b1.depth = 20;
b2.width = 5;
b2.height = 6;
b2.depth = 7;
b1.volume();
b2.volume();
}
}
Output:
Volume is 3000.0
Volume is 210.0
17. Program to explain Function with return value within class through Box class
class Box
{
double width;
double height;
double depth;
double volume()
{
return width * height * depth;
}
}
class BoxTest4
{
public static void main(String args[ ])
{
Box b1 = new Box();
Box b2 = new Box();
double vol;
b1.width = 10;
b1.height = 15;
b1.depth = 20;
b2.width = 5;
b2.height = 6;
b2.depth = 7;
vol = b1.volume();
System.out.println("Volume is " + vol);
vol = b2.volume();
System.out.println("Volume is " + vol);
}
}
Output:
Volume is 3000.0
Volume is 210.0
18. Program to initialize an object (private instance variable) using default constructor in Box class
class Box
{
private double width;
private double height;
private double depth;
void initBox(double w, double h, double d)
{
width = w;
height = h;
depth = d;
}
double volume()
{
return width * height * depth;
}
}
class BoxTest6
{
public static void main(String args[ ])
{
Box b1 = new Box();
Box b2 = new Box();
b1.initBox(10, 15, 20);
b2.initBox(5, 6, 7);
System.out.println("Volume is " + b1.volume());
System.out.println("Volume is " + b2.volume());
}
}
Output:
Volume is 3000.0
Volume is 210.0
19. Program to initialize an object (private instance variables) using default constructor in Box class
class Box
{
private double width;
private double height;
private double depth;
Box()
{
width = 10;
height = 10;
depth = 10;
}
double volume()
{
return width * height * depth;
}
}
class BoxTest7
{
public static void main(String args[ ])
{
Box b1 = new Box();
Box b2 = new Box();
System.out.println("Volume is " + b1.volume());
System.out.println("Volume is " + b2.volume());
}
}
Output:
Volume is 1000.0
Volume is 1000.0
20. Program to initialize an object (private intance variables) using parametrise constructor in Box class
class Box
{
private double width;
private double height;
private double depth;
Box(double w, double h, double d)
{
width = w;
height = h;
depth = d;
}
double volume()
{
return width * height * depth;
}
}
class BoxTest8
{
public static void main(String args[ ])
{
Box b1 = new Box(10, 15, 20);
Box b2 = new Box(5, 6, 7);
System.out.println("Volume is " + b1.volume());
System.out.println("Volume is " + b2.volume());
}
}
Output:
Volume is 3000.0
Volume is 210.0
21. Program to initialize an object (using this to un hide instance variable) using parameterised constructor in Box class
class Box
{
private double width;
private double height;
private double depth;
Box(double width, double height, double depth)
{
this.width = width;
this.height = height;
this.depth = depth;
}
double volume()
{
return width * height * depth;
}
}
class BoxTest9
{
public static void main(String args[ ])
{
Box b1 = new Box(10, 15, 20);
Box b2 = new Box(5, 6, 7);
System.out.println("Volume is " + b1.volume());
System.out.println("Volume is " + b2.volume());
}
}
Output:
Volume is 3000.0
Volume is 210.0
22. Program to initialize objects using different types of constructor in Box class ( Constructor Overloading )
class Box
{
private double width;
private double height;
private double depth;
Box()
{
width = 1;
height = 1;
depth = 1;
}
Box(double w, double h, double d)
{
width = w;
height = h;
depth = d;
}
Box(double len)
{
width = height = depth = len;
}
Box(Box b)
{
width = b.width;
height = b.height;
depth = b.depth;
}
double volume()
{
return width * height * depth;
}
}
class BoxTest10
{
public static void main(String args[ ])
{
Box b1 = new Box();
Box b2 = new Box(10, 15, 20);
Box b3 = new Box(10);
Box b4 = new Box(b2);
System.out.println("Volume is " + b1.volume());
System.out.println("Volume is " + b2.volume());
System.out.println("Volume is " + b3.volume());
System.out.println("Volume is " + b4.volume());
}
}
Output:
Volume is 1.0
Volume is 3000.0
Volume is 1000.0
Volume is 3000.0
23. Program to explain Passing Object to method
class Circle
{
private double radius;
Circle()
{
radius = 0.0;
}
Circle( double radius)
{
this.radius = radius;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CirclePassingObject
{
public static void main( String args[ ] )
{
Circle c1 = new Circle(20);
calcArea( c1 );
}
public static void calcArea( Circle c )
{
System.out.println(" Area of Circle : " + c.area());
}
}
Output:
Area of Circle : 314.0
24. Program to explain Returning Object from method
class Circle
{
private double radius;
Circle()
{
radius = 0.0;
}
Circle( double radius)
{
this.radius = radius;
}
public double area()
{
return 3.14 * radius * radius;
}
}
public class CircleReturningObject
{
public static void main( String args[ ] )
{
Circle c1;
c1 = createCircle();
calcArea( c1 );
}
public static Circle createCircle()
{
Circle c = new Circle( 10 );
return c;
}
public static void calcArea( Circle c )
{
System.out.println(" Area of Circle : " + c.area());
}
}
Output:
Area of Circle : 314.0
25. Program to use Nested Class.
class Outer
{
private int a;
Outer()
{
a = 10;
}
public class Inner
{
private int b;
Inner()
{
b = 20;
}
void showInner()
{
System.out.println(" b = " + b);
}
}
void showOuter()
{
System.out.println(" a = " + a);
}
}
class NestedCls1
{
public static void main( String args[ ] )
{
Outer otr = new Outer();
Outer.Inner inr = otr.new Inner();
otr.showOuter();
inr.showInner();
}
}
Output:
a = 10
b = 20
26. Program to explain that private variable of Outer class can be accessible in Inner class but private variable of Inner class can not be accessible in Outer class.
class Outer
{
private int a;
Outer()
{
a = 10;
}
public class Inner
{
private int b;
Inner()
{
b = 20;
}
void showInner()
{
System.out.println(" a = " + a);
System.out.println(" b = " + b);
}
}
void showOuter()
{
System.out.println(" a = " + a);
// System.out.println(" b = " + b); // Error
}
}
class NestedCls2
{
public static void main( String args[ ] )
{
Outer otr = new Outer();
Outer.Inner inr = otr.new Inner();
otr.showOuter();
inr.showInner();
}
}
Output:
a = 10
a = 10
b = 20
27. Program to create Inner class Object in Outer class.
class Outer
{
private int a;
Outer()
{
a = 10;
}
public class Inner
{
private int b;
Inner()
{
b = 20;
}
void showInner()
{
System.out.println(" b = " + b);
}
}
void showOuter()
{
Inner inr = new Inner();
System.out.println(" a = " + a);
inr.showInner();
}
}
class NestedCls3
{
public static void main( String args[ ] )
{
Outer otr = new Outer();
otr.showOuter();
}
}
Output:
a = 10
b = 20
28. Program to explain Static Inner Class.
class Outer
{
private int a;
Outer()
{
a = 10;
}
public static class Inner
{
private int b;
Inner()
{
b = 20;
}
void showInner()
{
System.out.println(" b = " + b);
}
}
void showOuter()
{
System.out.println(" a = " + a);
}
}
class NestedCls4
{
public static void main( String args[ ] )
{
Outer otr = new Outer();
Outer.Inner inr = new Outer.Inner();
otr.showOuter();
inr.showInner();
}
}
Output:
a = 10
b = 20
29. Program to explain that the Inner class can be defined within the method, loop, if-block or any other block.
class Outer
{
int outer_x = 100;
void test()
{
for(int i=0; i<5; i++)
{
class Inner
{
void display()
{
System.out.println("outer_x = " + outer_x);
}
}
Inner inr = new Inner();
inr.display();
}
}
}
class NestedCls20
{
public static void main(String args[ ])
{
Outer otr = new Outer();
otr.test();
}
}
Output:
outer_x = 100
outer_x = 100
outer_x = 100
outer_x = 100
outer_x = 100
30. Program to use Factory method to create Inner class Objects.
class Outer
{
class Inner
{
private int x = 10;
public int getX()
{
return x;
}
}
public Inner createInner()
{
return new Inner();
}
public void show()
{
Inner inr = createInner();
System.out.println(" x : " + inr.getX());
}
}
class NestedCls9
{
public static void main(String[] args)
{
Outer otr = new Outer();
otr.show();
}
}
Output:
x : 10
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