Java File pro

Write a program to find maximum repeated words from a file

package com.java2novice.algos;

import java.io.BufferedReader;

import java.io.DataInputStream;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.StringTokenizer;

import java.util.Map.Entry;

public class MaxDuplicateWordCount

{

public Map getWordCount(String fileName)

{ 

        FileInputStream fis = null;

        DataInputStream dis = null;

        BufferedReader br = null;

        Map wordMap = new HashMap();

        try

        {

            fis = new FileInputStream(fileName);

            dis = new DataInputStream(fis);

            br = new BufferedReader(new InputStreamReader(dis));

            String line = null;

            while((line = br.readLine()) != null)

            {

                StringTokenizer st = new StringTokenizer(line, " ");

                while(st.hasMoreTokens())

                 {

                    String tmp = st.nextToken().toLowerCase();

                    if(wordMap.containsKey(tmp))

                    {

                        wordMap.put(tmp, wordMap.get(tmp)+1);

                    }

                     else

                    {

                        wordMap.put(tmp, 1);

                    }

                }

            }

        }

         catch (FileNotFoundException e)

        {

            e.printStackTrace();

        }

        catch (IOException e)

       {

            e.printStackTrace();

        }

         finally

         {

            try{if(br != null) br.close();}catch(Exception ex){}

        }

        return wordMap;

    }

    public List> sortByValue(Map wordMap)

{

        Set> set = wordMap.entrySet();

        List> list = new ArrayList>(set);

        Collections.sort( list, new Comparator

        {

            public int compare( Map.Entry o1, Map.Entry o2 )

            {

                return (o2.getValue()).compareTo( o1.getValue() );

            }

        } );

        return list;

    }

    public static void main(String a[])

   {

        MaxDuplicateWordCount mdc = new MaxDuplicateWordCount();

        Map wordMap = mdc.getWordCount("C:/MyTestFile.txt");

        List> list = mdc.sortByValue(wordMap);

        for(Map.Entry entry:list){

            System.out.println(entry.getKey()+" ==== "+entry.getValue());

        }

    }

}

Write a program to find out duplicate characters in a string

package com.java2novice.algos;

import java.util.HashMap;

import java.util.Map;

import java.util.Set;

public class DuplicateCharsInString

{

public void findDuplicateChars(String str)

{

         Map dupMap = new HashMap();

        char[] chrs = str.toCharArray();

        for(Character ch:chrs)

           {

            if(dupMap.containsKey(ch))

           {

                dupMap.put(ch, dupMap.get(ch)+1);

            }

            else

          {

                dupMap.put(ch, 1);

            }

        }

        Set keys = dupMap.keySet();

        for(Character ch:keys)

        {

            if(dupMap.get(ch) > 1)

           {

                System.out.println(ch+"--->"+dupMap.get(ch));

            }

        }

    }

    public static void main(String a[])

    {

        DuplicateCharsInString dcs = new DuplicateCharsInString();

        dcs.findDuplicateChars("Java2Novice");

    }

}

Write a program to find top two maximum numbers in a array

package com.java2novice.algos;

public class TwoMaxNumbers

{

public void printTwoMaxNumbers(int[] nums)

{

        int maxOne = 0;

        int maxTwo = 0;

        for(int n:nums)

        {

            if(maxOne < n)

           {

                maxTwo = maxOne;

                maxOne =n;

            }

            else if(maxTwo < n)

            {

                maxTwo = n;

            }

        }

        System.out.println("First Max Number: "+maxOne);

        System.out.println("Second Max Number: "+maxTwo);

    }

    public static void main(String a[])

    {

        int num[] = {5,34,78,2,45,1,99,23};

        TwoMaxNumbers tmn = new TwoMaxNumbers();

        tmn.printTwoMaxNumbers(num);

    }

}

Write a program to sort a map by value

package com.java2novice.algos;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.Map.Entry;

public class OrderByValue

{

public static void main(String a[])

{

        Map map = new HashMap();

        map.put("java", 20);

        map.put("C++", 45);

        map.put("Java2Novice", 2);

        map.put("Unix", 67);

        map.put("Mac", 26);

        map.put("Why this kolavari", 93);

        Set> set = map.entrySet();

        List> list = new ArrayList>(set);

        Collections.sort( list, new Comparator

        {

         public int compare( Map.Entry o1, Map.Entry o2 )

            {

                return (o2.getValue()).compareTo( o1.getValue() );

            }

        } );

        for(Map.Entry entry:list)

        {

            System.out.println(entry.getKey()+" ==== "+entry.getValue());

        }

    }

}