First Servlet Example

FirstServlet.java
public class FirstServlet implements javax.servlet.Servlet
{
public void init(javax.servlet.ServletConfig sc) throws javax.servlet.ServletException
{
System.out.println("In init");
}
public void service(javax.servlet.ServletRequest req,javax.servlet.ServletResponse res) throws javax.servlet.ServletException,java.io.IOException
{
System.out.println("In service");

java.io.PrintWriter out=res.getWriter();

out.println("Hello from First Servlet");
}
public void destroy()
{
System.out.println("In destroy");
}//destroy

public String getServletInfo()
{
return "FirstServlet";
}
public javax.servlet.ServletConfig getServletConfig()
{
//should return ServletConfig
return null;
}//getServletConfig

}//class

Calender Example in java

import java.util.Calendar;

public class CalendarExample
{
public static void main(String[] args)
{
Calendar cal = Calendar.getInstance();
int day = cal.get(Calendar.DATE);
int month = cal.get(Calendar.MONTH) + 1;
int year = cal.get(Calendar.YEAR);
int dow = cal.get(Calendar.DAY_OF_WEEK);
int dom = cal.get(Calendar.DAY_OF_MONTH);
int doy = cal.get(Calendar.DAY_OF_YEAR);

System.out.println("Current Date: " + cal.getTime());
System.out.println("Day: " + day);
System.out.println("Month: " + month);
System.out.println("Year: " + year);
System.out.println("Day of Week: " + dow);
System.out.println("Day of Month: " + dom);
System.out.println("Day of Year: " + doy);
}
}

Program for Calculating Subject Marks in Java

package pkg;
import java.io.*;
public class Subjects
{

public static void main(String[] args)throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("How many numbers ?");
int n=Integer.parseInt(br.readLine());
int marks[]=new int[n];
for(int i=0;i<n;i++)
{
System.out.println("Enter the marks:");
marks[i]= Integer.parseInt(br.readLine());
}
int tot=0;
System.out.println("The marks are :");
for(int i=0;i<n;i++)
{
System.out.println(marks[i]);
tot=tot+marks[i];
}
System.out.println("Total marks are :"+tot);
float percent = (float)tot/n ;
System.out.println("percentage = "+percent);
System.out.println("Length of array is "+marks.length);
}


}

Interfaces in Java

Interfaces
//interface example
interface Inter
{
void connect();
}
//implementation classes
class Oracle implements Inter
{
public void connect()
{
System.out.println("Connecting to Oracle database..........");
}
}
class Sybase implements Inter
{
public void connect()
{
System.out.println("Connecting to sybase database..............");
}
}
class Interface
{
public static void main(String[] args) throws Exception
{
//Accepting database name from commandline args & store it in an obj c

Class c = Class.forName(args[0]);
{
//create an obj to that class whose name is in c

MyInter mi=(MyInter)c.newInstance();
{
//call conect method of obj

mi.connect();

}

}

}

}