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();

}

}

}

}