A Sample Java Programs & compilation

A Sample java programs

Q. write a Java program which will display the sum of two number ?

program:

class Sum                 //Sub class

{

int a,b,c;                     // Data members

void set( )                  // non - static methods

{

a=10;

b=20;

}

void sum( )                 // Method Declaration 

{

c=a+b;

}

void display( )           // Display the values

{

System.out.println("value of a="+a);

System.out.println("value of b="+b);

System.out.println("Sum="+c);

}

}//Business logic

class SumDemo    // Mainclass

{

public static void main(String args[])    // Main Method

{

Sum s=new Sum( );    // Object declaration with sub class called Sum

s.set( );                           

s.sum( );                        // methods callings

s.display( );

}

}// Execution logic

➩ Compile the above java program in command prompt.

cd> javac Sum.java ⤶
cd> java Sum ⤶
Output:-  30.

                                  

Q . write a Java program which will display the multiply of two number ?.

Program:

class Mul 
{
int a,b,c;
void set()
{
a=10;
b=20;
}
void mul()
{
c=a*b;
}
void display()
{
System.out.println("value of a="+a);
System.out.println("value of b="+b);

System.out.println("multiplication="+c);

}
}
class MulDemo
{
public static void main(String args[])
{
Mul m=new Mul();
m.set();
m.mul();
m.display();
}
}

Q . write a Java program which will display the "Division of two number" ?.

Program:-

class Division 
{
int a,b,c;
void set()
{
a=4;
b=2;
}
void mul()
{
c=a/b;
}
void display()
{
System.out.println("value of a="+a);
System.out.println("value of b="+b);

System.out.println("multiplication="+c);

}
}
class DivisionDemo
{
public static void main(String args[])
{
Division m=new Division();
m.set();
m.mul();
m.display();
}
}

Q. write a Java program which will display the  "Area Of Triangle" ?.

Program :

class Triangle

{

int b,h,a;

void set();

{

b=1;

h=2;

}

void areaOfTriangle()

{

a = 0.5*b*h;

}

void display()

{

System.out.println("value of b="+b);

System.out.println("value of h="+h);

System.out.println("AreaOfTriangle="+a);

}

}

class TriangleDemo

{

public static void main(String args[])

{

Triangle t=new Triangle();

t.set();

t.areaOfTriangle();

t.display();

}

}

Q. write a Java program which will display the  "PerimeterOfRectangle" ?.

program:

class PerimeterOfRectangle
{
int l,b,p;
void set()
{
l=10;
b=20;
}
void perimeterOfRectangle()
{
p=2*l*b;
}
void display()
{
System.out.println("value of l="+l);
System.out.println("value of b="+b);
System..out.println("perimeterofrectangle="+p);
}
}
class PerimeterDemo
{
public static void main(String args[])
{
PerimeterOfRectangle p= new PerimeterOfRectangle();
p.set();
p.perimeterOfRectangle();
p.display();
}
}

Q. write a Java program which will display the  "AreaOfTrapezoid" ?.

program:

class AreaOfTrapezoid
{
int b1,b2,h;
float a;
void set()
{
b1=2;
b2=3;
h=4;
}
void areaOfTrapezoid()
{
a=b1+b2*h*0.5;
}
void display()
{
System.out.println("value of b1="+b1);
System.out.println("value of b2="+b2);
System.out.println("areaoftrapezoid="+a);
}
}
class AreaDemo
{
public static void main(String args[])
{
AreaOfTrapezoid a=new AreaOfTrapezoid();
a.set();
a.areaOfTrapezoid();
a.display();
}
}

Q. write a Java program which will display the  "SlopeOfLine" ?.

Program :

class SlopeOfLine
{
int x1,x2,y1,y2;
float m;
void set()
{
x1=1;
x2=2;
y1=2;
y2=4;
}
void slopeOfLine()
{
m=y2-y1/x2-x1;
}
void display()
{
System.out.println("value of x1="+x1);
System.out.println("value of x2="+x2);
System.out.println("value of y1="+y1);
System.out.println("value of y2="+y2);
System.out.println("slopeofline="+m);
}
}
class SlopeDemo
{
public static void main(String args[])
{
SlopeOfLine s= new SlopeOfLine();
s.set();
s.slopeOfLine();
s.display();
}
}

Q. write a Java program which will display the  "Volume of a Cone" ?.

Program :

class VolumeOfCone
{
int b,h;
float v;
void set()
{
b=2;
h=3;
}
void volumeOfCone()
{
v=b*h*0.3;
}
void display()
{
System.out.println("value of b="+b);
System.out.println("value of h="+h);
System.out.println("volume of a cone="+v);
}
}
class ConeDemo
{
public static void main(String args[])
{
VolumeOfCone= new VolumeOfCone();
s.set();
s.volumeOfCone();
s.display();
}

}

Q. write a Java program which will display the  "SurfaceAreaOfCyclinder" ?.

Program :

class SurfaceAreaOfCyclinder
{
int r,h;
float pi,s;
void set()
{
r=2;
h=3;
pi=3.14f;
}
void surfaceAreaOfCyclinder()
{
s=2*pi*r*h;
}
void display()
{
System.out.println("value of r="+r);
System.out.println("value of h="+h);
System.out.println("SurfaceAreaOfCyclinder="+s);
}
}
class AreaOfCyclinder
{
public static void main(String args[])
{
SurfaceAreaOfCyclinder= new SurfaceAreaOfCyclinder();
s.set();
s.surfaceAreaOfCyclinder();
s.display();
}
}

Compile and set the class path in java:

Now we will discuss about on  how to set the class path for compiling  & executing the java program. The  given below points are  understand that how to compile the java program piratically. 

1) Firstly we can create a folder/directory  in any drive option of my computer and save your program in that folder .  Here i will create a folder in  D: (Drive)  with name as Java .

Here i  save the program with file name in that folder with extension  called  ".java".

Example:- D: Java ➡️ FirstProgram.java (File name)

2)  Compile the Java program like this .

 Example:-  D://cd  java ➡️ D://java> Javac FirstProgram.java (file name) ↵

3) Error will occur like this "Javac is not recognized as internally and externally command ".

4) Now, we have to set the path for javac & java tools .

Example :- D:// java>set path="C:\Program Files\Java\ jdk 1.8.0_144\bin";

5) Again we recompile the java program .
Example :- D:// java> javac  FirstProgram.java↵

6) To ensure that FirstProgram.class file name is generated when we compile the java program .  

7) Run the java program .
Example:-  D://java>java FirstProgram ↵

When the above statements is executed the following operations will be performed.

1. ClassLoader subsystem loads/transfer FirstProgram.class file in to "MainMemmory" .
2. JVM takes loaded classes (FirstProgram).
3. JVM looks for main method  in the form of Array Of Object Of String class "(String args [])" .
4. JVM calls main (String args[]) with respect to  the loaded classes as FirstProgram.java
5. Finally we get the output of the program.