List of Java Programs

Java program – Type casting [converting from float to an integer]

class Typecast
{
public static void main(String args[])
{
float a=2.3333f;
int b=10;
int c=(int)a+b;
System.out.println(c);
}
}

Java Program – use of all data types.

class vari
{
public static void main(String args[])
{
int a=3;
String str="Hello World!";
float f=2.333f;
double d=1.22222;
System.out.println(str);
System.out.println(a);
System.out.println(f);
System.out.println(d);
}
}

Java program – Switch demo

class switchDemo
{
public static void main(String args[])
{
char day='S';
switch(day)
{
case 'M':
System.out.println("Monday");
break;

case 'T':
System.out.println("Tuesday");
break;

case 'W':
System.out.println("Wednesday");
break;

default:
System.out.println("Invalid day of the week");
break;
}
}
}

Java Program to add two numbers using DataInputStream

import java.io.*;
class inp
{
public static void main(String args[])
{
int a,b,c;
try
{
DataInputStream in=new DataInputStream(System.in);
System.out.print("Enter val for a:");
a=Integer.parseInt(in.readLine());
System.out.print("Enter val for b:");
b=Integer.parseInt(in.readLine());
c=a+b;
System.out.print("SUM:"+c);
}
catch(IOException e)
{}
}
}

Java program to print person name and age

import java.io.DataInputStream;

class inp2
{
public static void main(String args[])
{
int age;
String name;
DataInputStream in=new DataInputStream(System.in); 
try
{
System.out.print("Enter Name:");
name=in.readLine();

System.out.print("Enter age:");
age=Integer.parseInt(in.readLine());

System.out.println("Name="+name);
System.out.println("Age="+age);
}
catch(Exception e) {}
}
}

Java Program to use Constructor

class Books
{
String title, auth;
int rate;

Books()
{
title="C Book";
auth="BSwamy";
rate=150;
System.out.println("Books details");
System.out.println("Book Title: "+title);
System.out.println("AuthorName:"+auth);
System.out.println("Book Price:"+rate);
}
}
class ConTest
{
public static void main(String args[])
{
Books b=new Books();
}
}

Java Program to display 3 employees name and salary.

import java.io.*;
class Emp3
{
public static void main(String args[])
{
int i, sal;
String nm;
try
{
DataInputStream in=new DataInputStream(System.in);
System.out.println("Enter 3 Employees info : Name and 

salary:");
for(i=0; i<3; i++)
{
nm=in.readLine();
sal=Integer.parseInt(in.readLine());
System.out.println(i+1+": Employee Info...............................");
System.out.println("Name : " + nm);
System.out.println("Salary : " + sal);
}
}
catch(IOException e) {}
}
}

Java Program to print Employee name, Department and Total salary.

class Emp
{
String ename, dept;
int bs,bn,sal;
void show()
{
ename="Amit";
dept="Accts";
bs=12000;
bn=1000;
sal=bs+bn;
System.out.println("Details of Employee");
System.out.println("Employee Name:"+ename);
System.out.println("Department:"+dept);
System.out.println("Total Salary"+sal);
}
}
class Emp_Dets
{
public static void main(String args[])
{
Emp e=new Emp();
e.show();
}
}

Java Program to print Vector and Enumeration

import java.util.*;
public class EnumTest 
{
public static void main(String args[]) 
{
      Enumeration days;

      Vector dayNames = new Vector();

      dayNames.add("Sunday");
      dayNames.add("Monday");
      dayNames.add("Tuesday");
      dayNames.add("Wednesday");
      dayNames.add("Thursday");
      dayNames.add("Friday");
      dayNames.add("Saturday");

      days = dayNames.elements();
 while (days.hasMoreElements())
{
System.out.println(days.nextElement()); 
  }
 }
}

Java Program to print Inventory information with use of Exception Handling.

import java.io.*;
class Err
{
public static void main(String args[])
{
String pnm;
int r, q, t;
try
{
DataInputStream in=new DataInputStream(System.in);
System.out.print("Enter Pname:");
pnm=in.readLine();
System.out.print("Enter Rate:");
r=Integer.parseInt(in.readLine());
System.out.print("Enter Qty:");
q=Integer.parseInt(in.readLine());
t=q*r;
System.out.println("\t Product Details\n ");
System.out.println("\t Product Name:  "+pnm);
System.out.println("\t Product Rate "+r);
System.out.println("\t Product Qty:  "+q);
System.out.println("\t======================");
System.out.println("\t Total amount:  "+t);
}
catch(IOException ie) {}
catch(NumberFormatException ne) 
{
System.out.println("\tData Invalid ");
}
}
}

Java Program to show ArrayIndexOutOfBoundsException

class Err2
{
public static void main(String args[])
{
int arr[]={1,2,3,4};
try
{
System.out.println(arr[0]);
System.out.println(arr[1]);
System.out.println(arr[2]);
System.out.println(arr[3]);
System.out.println(arr[4]);
}
catch(ArrayIndexOutOfBoundsException ae)
{
System.out.println("Array index is out of range");
}
finally
{
System.out.println("Finally, Program Executed successfully");
}
}
}

Java Program to show Arithmetic Exception and Invalid number [Divide by Zero / Number Format Exception]

import java.io.*;

class Err4
{
public static void main(String args[])
{

int n1,n2,res;
try
{
DataInputStream in=new DataInputStream(System.in);
System.out.print("Enter num1:");
n1=Integer.parseInt(in.readLine());
System.out.print("Enter num2:");
n2=Integer.parseInt(in.readLine());
res=n1/n2;
System.out.print("Div:"+res);
}

catch(IOException ie) {}
catch(NumberFormatException ne) 
{
System.out.println("\tData Invalid ");
}
catch(ArithmeticException ae) 
{
System.out.println("Divide by Zero err...");
}
}
}

Java Program to show Method Over Loading

class Disp
{
int x,y;
Disp()
{
System.out.println("No Parameter........");
}

Disp(int a, int b)
{
x=a;
y=b;
System.out.println("With Parameter...");
System.out.println("X: "+x);
System.out.println("Y: "+y);
}
}

class Mover
{
public static void main(String args[])
{
Disp d=new Disp();
Disp e=new Disp(2,3);
}
}

Java Program to show Method Overriding

class Base
{
void show()
{
System.out.println("inside the Base class method");
}
}

class Derive extends Base
{
void show()
{
System.out.println("inside the Dervied class method");
}
}

class Override
{
public static void main(String args[])
{
Derive d=new Derive();
d.show();
}
}

Java Program to print Multiplication Table from 1 to 10.

class MT
{
public static void main(String args[])
{
int i,j;

for(i=1; i<=10; i++)
{
for(j=1; j<=10; j++)
{
System.out.print("\t"+i*j);
}
System.out.println("\n");
}
}
}