DirList example in java program using file handling

import java.io.*;

class DirList {

      public static void main(String args[]) {

      String dirname="/subha";

      File f1=new File(dirname);

        if(f1.isDirectory()) {

            System.out.println("Directory of " + dirname);

            String s[]=f1.list();

            for(int i=0;i<s.length;i++)

            {

                    File f=new File(dirname + "/" +s[i]);

                    if(f.isDirectory()) {

                            System.out.println(s[i] + " is a Directory");

                    }

            else

             {

                            System.out.println(s[i] + " is a File");

              }

                    }

       }

      else

            {

                         System.out.println(dirname + " is not a directory");

             }

       }

}

Directory of .HTML Files

    // Directory of .HTML Files

        import java.io.*;

        class DirListOnly {

        public static void main(String args[]) {

                String dirname="/subha/html";

                File f1=new File(dirname);

                FilenameFilter only=new OnlyExt("html");

                String s[]=f1.list(only);

                for(int i=0;i<s.length;i++) {

                        System.out.println(s[i]);

                }

             }

        }

FilenameFilter example in java

import java.io.*;

class OnlyExt implements FilenameFilter {

        String ext;

        public OnlyExt(String ext)

       {

        this.ext="."+ ext;

        }

        public boolean accept(File dir,String name)

        {

        return name.endsWith(ext);

        }

}

stack example java program using interface

IntStack.java

interface IntStack {

        void push(int item);

        int pop();

}

FixedStack.java

class FixedStack implements IntStack {

        private int stack[];

        private int tos;

        FixedStack(int size)

        {

        stack=new int[size];

        tos=-1;

        }

        public void push(int item)

        {

        if(tos==stack.length-1)

                System.out.println("stack is full");

        else

                stack[++tos]=item;

        }

        public int pop()

        {

        if(tos<0)

        {

                System.out.println("stack underflow");

                return 0;

        }

        else

                return stack[tos--];

        }

        public static void main(String args[]) {

                FixedStack mystack1=new FixedStack(5);

                FixedStack mystack2=new FixedStack(8);

                for(int i=0;i<6;i++) mystack1.push(i);

                for(int i=0;i<9;i++) mystack2.push(i);

                System.out.println("stack in mystack1");

                for(int i=0;i<6;i++)

                System.out.println(mystack1.pop());

                System.out.println("stack in mystack2");

                for(int i=0;i<9;i++)

                System.out.println(mystack2.pop());

        }

}

interface example java program

Callback.java

interface Callback

{

        public void call(int param);

}

Client.java

class Client implements Callback

{

        public void call(int p)

        {

                System.out.println("Interface Method = " + p);

        }

        public void nonIfaceMeth()

        {

                System.out.println("Non Interface method is also used");

        }

        public static void main(String args[])

        {

                Callback c = new Client();

                c.call(5);

       //         c.nonIfaceMeth();

        }

}

multilevel with constructor example java program

//multilevel with constructor

 class students1

{

        private int sno;

        private String sname;

        students1(int no,String name)

        {

                sno = no;

                sname = name;

        }

        public void dispstud()

        {

                System.out.println("Student No : " + sno);

                System.out.println("Student Name : " + sname);

        }

}

class marks1 extends students1

{

        protected int mark1,mark2;

        marks1(int n1,int n2,int sno,String sname)

        {

                super(sno,sname);

                mark1 = n1;

                mark2 = n2;

        }

        public void dispmarks()

        {

                System.out.println("Mark1 : " + mark1);

                System.out.println("Mark2 : " + mark2);

        }

}

class finaltot1 extends marks1

{

        private int total;

        finaltot1(int n1,int n2,int no,String name)

        {

                super(n1,n2,no,name);

                total = mark1 + mark2;

        }

        public void disptotal()

        {

                System.out.println("Total : " + total);

        }

        public static void main(String args[])

        {

                finaltot1 f = new finaltot1(90,89,100,"Kirthika");

                f.dispstud();

                f.dispmarks();

                f.disptotal();

        }

}

multilevel inheritance example java program

class students

{

        private int sno;

        private String sname;

        public void setstud(int no,String name)

        {

                sno = no;

                sname = name;

        }

        public void putstud()

        {

                System.out.println("Student No : " + sno);

                System.out.println("Student Name : " + sname);

        }

}

class marks extends students

{

        protected int mark1,mark2;

        public void setmarks(int m1,int m2)

        {

                mark1 = m1;

                mark2 = m2;

        }

        public void putmarks()

        {

                System.out.println("Mark1 : " + mark1);

                System.out.println("Mark2 : " + mark2);

        }

}

class finaltot extends marks

{

        private int total;

        public void calc()

        {

                total = mark1 + mark2;

        }

        public void puttotal()

        {

                System.out.println("Total : " + total);

        }

        public static void main(String args[])

        {

                finaltot f = new finaltot();

                f.setstud(100,"Nithya");

                f.setmarks(78,89);

                f.calc();

                f.putstud();

                f.putmarks();

                f.puttotal();

        }

}