function to print the repeated values in an array with it's count

public static void printRepeating(int arr[], int size)

{

int i,j;

System.out.println("The repeating elements are : ");

HashMap<Integer, Integer> hmap = new HashMap<>();

for (i = 0; i < size-1; i++)

{

int c=1;

for (j = i+1; j < size; j++)

{

if(arr[i]==arr[j]){

c++;

}

}

if(c>1&& !hmap.containsValue(arr[i])){

hmap.put(c,arr[i]);

}

}

for (int k:hmap.keySet()){

System.out.println(hmap.get(k)+" : count "+k);

}

}

java program to download file from url

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

public class URLReader {

    public static void copyURLToFile(URL url, File file) {

        try {
            InputStream input = url.openStream();
            if (file.exists()) {
                if (file.isDirectory())
                    throw new IOException("File '" + file + "' is a directory");

                if (!file.canWrite())
                    throw new IOException("File '" + file + "' cannot be written");
            } else {
                File parent = file.getParentFile();
                if ((parent != null) && (!parent.exists()) && (!parent.mkdirs())) {
                    throw new IOException("File '" + file + "' could not be created");
                }
            }

            FileOutputStream output = new FileOutputStream(file);

            byte[] buffer = new byte[4096];
            int n = 0;
            while (-1 != (n = input.read(buffer))) {
                output.write(buffer, 0, n);
            }

            input.close();
            output.close();

            System.out.println("File '" + file + "' downloaded successfully!");
        }
        catch(IOException ioEx) {
            ioEx.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {

        //URL pointing to the file
        String sUrl = "https://singztechmusings.files.wordpress.com/2011/09/maven_eclipse_and_osgi_working_together.pdf";

        URL url = new URL(sUrl);

        //File where to be downloaded
        File file = new File("home\\sujith\\IdeaProjects\\downloadTest");

        URLReader.copyURLToFile(url, file);
    }

}

java program to download a file from an external url

import java.io.BufferedInputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URL;

import org.apache.commons.io.FileUtils;

public class FileDownloadTest {

public static void main(String[] args) {

try {

// Make sure that this
directory exists

String dirName = "home\\sujith\\FileDownload";

System.out.println("Downloading \'Maven, Eclipse and OSGi
working together\' PDF document...");

saveFileFromUrlWithJavaIO(

dirName +
"\\maven_eclipse_and_osgi_working_together.pdf",

"https://singztechmusings.files.wordpress.com/2011/09/maven_eclipse_and_osgi_working_together.pdf");

System.out.println("Downloaded \'Maven, Eclipse and OSGi working
together\' PDF document.");

System.out.println("Downloading \'InnoQ Web Services Standards
Poster\' PDF document...");

saveFileFromUrlWithCommonsIO(

dirName +
"\\innoq_ws-standards_poster_2007-02.pdf",

"http://singztechmusings.files.wordpress.com/2011/08/innoq_ws-standards_poster_2007-02.pdf");

System.out.println("Downloaded \'InnoQ Web Services Standards
Poster\' PDF document.");

} catch (MalformedURLException
e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

// Using Java IO

public static void
saveFileFromUrlWithJavaIO(String fileName, String fileUrl)

throws
MalformedURLException, IOException {

BufferedInputStream in = null;

FileOutputStream fout = null;

try {

in = new
BufferedInputStream(new URL(fileUrl).openStream());

fout = new
FileOutputStream(fileName);

byte data[] = new
byte[1024];

int count;

while ((count =
in.read(data, 0, 1024)) != -1) {

fout.write(data, 0,
count);

}

} finally {

if (in != null)

in.close();

if (fout != null)

fout.close();

}

}

// Using Commons IO library

// Available at
http://commons.apache.org/io/download_io.cgi

public static void
saveFileFromUrlWithCommonsIO(String fileName,

String fileUrl) throws MalformedURLException, IOException
{

FileUtils.copyURLToFile(new
URL(fileUrl), new File(fileName));

}

}

//https://mvnrepository.com/artifact/commons-io/commons-io/2.4

Java Program to Generate the all Non repeated sequence of the Array values

package p1;
import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
/**
 *
 * @author sujith
 */
class ticketGenerator {

    static void ticketGenerator(int arr[], int n, int r, int index,
                                int data[], int i,ArrayList ar)
    {
       
        if (index == r)
        {
            int arr1[]= new int[r];
            String st="";
            for (int j=0; j<r; j++){
                arr1[j]=data[j];
                st=st+data[j]+" ";
            }
            pHelper(arr1,0,ar);
            ar.add(st);
        return;
        }
        if (i >= n)
            return;
        data[index] = arr[i];
        ticketGenerator(arr, n, r, index+1, data, i+1,ar);
        ticketGenerator(arr, n, r, index, data, i+1,ar);
    }

    static void printTicket(int arr[], int n, int r,ArrayList ar)
    {
        int data[]=new int[r];
        ticketGenerator(arr, n, r, 0, data, 0,ar);
    }
   
   
private static void pHelper(int[] arr, int index,ArrayList mylist){
    if(index >= arr.length - 1){
        String st="";
        for(int i = 0; i < arr.length - 1; i++){
            st=st+arr[i]+" ";
        }
        if(arr.length > 0) {
            st=st+arr[arr.length - 1];
        }
        mylist.add(st);
        return;
    }

    for(int i = index; i < arr.length; i++){
        int t = arr[index];
        arr[index] = arr[i];
        arr[i] = t;
        pHelper(arr, index+1,mylist);
        t = arr[index];
        arr[index] = arr[i];
        arr[i] = t;
    }
}
    public static void main (String[] args) {
        Scanner sc=new Scanner(System.in);
        ArrayList<String> ar= new ArrayList<>();
        System.out.println("Enter the number of Tickets");
        int n=sc.nextInt();
        int arr[]= new int[n];
        System.out.println("Enter the Tickets");
        for (int i = 0; i < n; i++) {
            arr[i]=sc.nextInt();
        }
        System.out.println("Enter the  generation sequence limit");
        int r =sc.nextInt();
        printTicket(arr, n, r,ar);
        Collections.shuffle(ar);
        System.out.println("The generated Keys");
        for (String temp : ar) {
            System.out.println(temp);
        }
    }
}

csv file processing in java

 */
/**/package excel
import java.io.*;
import java.util.StringTokenizer;

public class Cl1 {

public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub

String name;
String roll;
int marks;

File f = new File("C:\\Users\\user\\Documents\\cvv2.csv"); // file path, please change as per your requirements
int ss = size(f);
System.out.println(ss);
String sen[][] = new String [ss][2];
//get the classes ready for file reading

FileInputStream fis = new FileInputStream(f);
InputStreamReader isr = new  InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);

//-------------------------------------------

String line="";
int index=0;

while((line=br.readLine())!=null){ //read each line
StringTokenizer t = new StringTokenizer(line,","); // split the words
while(t.hasMoreTokens()){
sen[index][0] = t.nextToken();  // store first  word in the zeroth position of the matrix
sen[index++][1] = t.nextToken();// store second word in the first position of the matrix


}

}
//close all the necessary file objects.
fis.close();
   isr.close();
   br.close();
   //modify
   FileWriter fr = new FileWriter(f); // open file writer
   System.out.println("Increment roll numbers by  and store again: ");
   fr.write("Name,Roll\n"); // write the header
   int j=1;
   while(j<ss){
    //sen
    sen[j][1] = Integer.toString(Integer.parseInt(sen[j][1])+5);
    fr.write(sen[j][0]+","+sen[j++][1]+"\n");
   }
   fr.close();
   read(f);
   //modify
 
 
}
static void read(File f) throws IOException{ // function to display file content
FileInputStream fis = new FileInputStream(f);
InputStreamReader isr = new  InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
String line;
while((line = br.readLine())!=null){
System.out.println(line);
}
fis.close();
br.close();
isr.close();

}
static int size(File ff){// function to get the total lines in the file including the header
File f = ff;
int si = 0;
FileInputStream fis;
try {
System.out.println(f);
fis = new FileInputStream(f);
InputStreamReader isr = new  InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
String line="";

while((br.readLine())!=null){
si++;
}

fis.close();
   isr.close();
   br.close();
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("gggg");
e.printStackTrace();
}

return si;
}

}

arraylist with iterator in java

package p1;
import java.io.File;
import java.io.*;
import java.util.*;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author sujith
 */
public class fileprgm {
 
    public static void main(String[] args) {
        File f1 = new File("e:\\data6.csv");
        try {
            BufferedReader br= new BufferedReader(new InputStreamReader(new FileInputStream(f1)));
            String line;
            List<String> ar = new ArrayList<String>();
            while((line=br.readLine())!=null){
                StringTokenizer st= new StringTokenizer(line,",");
                while(st.hasMoreTokens()){
             
                 
                    ar.add(st.nextToken());
                         
                }
             
            }
         

            Iterator<String> crunchifyIterator = ar.iterator();
while (crunchifyIterator.hasNext()) {

                        if(crunchifyIterator.hasNext()){
                           System.out.print(crunchifyIterator.next()+" ");
                        }
                        if(crunchifyIterator.hasNext()){
                           System.out.print(crunchifyIterator.next()+" ");
                        }
                        if(crunchifyIterator.hasNext()){
                           System.out.print(crunchifyIterator.next()+" ");
                        }

                        System.out.print("\n");
}
        } catch (Exception ex) {
            Logger.getLogger(msuppu.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
 
}

file prgm csv,txt handling

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package p1;
import java.io.*;
import java.util.*;
import java.util.logging.Level;
import java.util.logging.Logger;


public class add_csv {
    public static void main(String[] args) {
        File f1= new File("E://data4.txt");
         BufferedReader br,br2;
         int size=0;
        try {
            br = new BufferedReader(new FileReader(f1));
              String line;
              int sum=0;
            while((line=br.readLine())!=null){
                StringTokenizer st= new StringTokenizer(line,",");
                while(st.hasMoreTokens()){
                    String p=st.nextToken();
                    //sum+=Integer.parseInt(p);
                    System.out.println(p);
                    size++;
                }
   
            }
            br.close();
            br2 = new BufferedReader(new FileReader("E://data4.txt"));
            FileOutputStream os= new FileOutputStream("E://copy4.txt");
            String[] myst= new String[size];
            int i=0;
            while((line=br2.readLine())!=null){
                 StringTokenizer st= new StringTokenizer(line,",");
                  while(st.hasMoreTokens()){
                    String p=st.nextToken();
                    myst[i++]=p;
                      //System.out.println(i);
                }
            }
            System.out.println(" ");
            for(int k=0;k<size;k++){
                for(int j=k+1;j<size;j++){
                    if(myst[k].compareTo(myst[j])>0){
                    String temp=myst[k];
                       // System.out.println("hi");
                    myst[k]=myst[j];
                    myst[j]=temp;
                    }
                }
            }
            for(String pintu:myst){
              System.out.println(pintu);  
              os.write(pintu.getBytes());
              os.write(" \n".getBytes());
            }
            System.out.println("The sum of integer is "+sum);  
        } catch (Exception ex) {
            Logger.getLogger(add_csv.class.getName()).log(Level.SEVERE, null, ex);
        }
         
    }
}

rough work 1 file read and write

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package p1;

import java.io.BufferedReader;
import java.io.File;
import java.io.*;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.*;

/**
 *
 * @author sujith
 */
public class str3 {
    public static void main(String[] args){
        File file= new File("C:\\data3.txt");
        File file2=new File("C:\\data3.txt");
       // String[] tokens = null;
        int k=0;
        try{
        //BufferedReader br= new BufferedReader(new InputStreamReader(new FileInputStream(file)));
            // BufferedReader br= new BufferedReader(new FileReader(f));
            BufferedReader br= new BufferedReader(new InputStreamReader(new FileInputStream(file)));
            FileInputStream in= new FileInputStream("C:\\data3.txt");
            FileOutputStream op= new FileOutputStream("E:\\data5.txt");
            //InputStreamReader ip=new InputStreamReader(in);          
            //OutputStreamWriter op= new OutputStreamWriter(new FileOutputStream("E:\\data4.txt"));
            //BufferedReader br= new BufferedReader(in);
           // System.out.println(ip);
            while((k=in.read())!=-1){
                System.out.println((char)k);
               // op.write(k);
               // op.append((char)k);
               // System.out.println((byte)k);
              
            }
        String line=null;
        int count=0;
        int i=0;
       
        while((line=br.readLine())!=null){
            //tokens=line.split("\\s+");
            StringTokenizer st= new StringTokenizer(line," ");
          
           while(st.hasMoreTokens()){
               String s=st.nextToken();
               char c;
               StringBuffer sb=new StringBuffer(s);
              for(int j=0;j<sb.length();j++){
                  for(int m=j+1;m<sb.length();m++){
                     // System.out.println(sb.ch);
                      //sb.setCharAt(i, ch);
                      if(sb.charAt(j)>sb.charAt(m)){
                          c=sb.charAt(j);
                          sb.setCharAt(j,sb.charAt(m));
                          sb.setCharAt(m, c);
                      }
                    
                  }
              }
              System.out.println(sb);
               //System.out.println(st.nextToken());             
               //StringBuffer sb=new StringBuffer(st.nextToken());
               // StringBuilder sb= new StringBuilder(st.nextToken());
               //String sb=st.nextToken();
              // String[] sb=new String[]{st.nextToken()};
               //System.out.println(sb.length);
              // System.out.println(st.nextToken());
              
              // op.write(st.nextToken().getBytes());
              // op.write(" ".getBytes());
              
               //System.out.println(st.nextToken().getClass().getName());
             
               op.write(sb.toString().getBytes());
               op.write(" ".getBytes());
           }
            op.write("\n".getBytes());
          
        }
       

        }catch(Exception e){
            System.out.println(e);
        }
    }
   
}

java Program to Implement Thread using Runnable Interface

Program to Implement Thread using Runnable Interface
class A implements Runnable
{
public void run()
{
for(int i=0; i<20; i++)
{
System.out.println(i);
}
}
}
class Run1
{
public static void main(String args[])
{
A a1 = new A();
Thread t = new Thread(a1);
t.start();
}
}

java program to Implement this and super Keyword

Program to Implement this and super Keyword
class vehicle
{
int id;
String color;
vehicle(int regno,String color)
{
id = regno;
this.color = color;
}
}
class vchl extends vehicle
{
int id;
String color;
vchl(int i1,int i2,String s1,String s2)
{
super(i2,s2);
id = i1;
color = s1;
}
void pdata()
{
System.out.print(super.id);
}
void ddata()
{
System.out.print(super.color);
}
public static void main(String arg[])
{
vchl v = new vchl(10,2334,"GREY","WHITE");
System.out.print("Vehicle color is ");
v.ddata();
System.out.print("\nVehicle number is ");
v.pdata();
System.out.println("\nVehicle engine color is "
+ v.color);
System.out.println("Vehicle engine id is " + v.id);
}
}
class single_inherit
{
public static void main(String a[])
{
radha m = new radha();
m.get(520,22000);
m.show1();
}
}

java Program to Implement the Concept of Inheritance

 Program to Implement the Concept of Inheritance
class prnt
{
int a, s;
void show()
{
System.out.println("Fathre name: Mr. Roshan Lal");
}
}
class radha extends prnt
{
void get(int x,int y)
{
a = x;
s = y;
}
void show1()
{
show();
System.out.println("Std name: Radha");
System.out.println("age:" + a);
System.out.println("salary:" + s);
}
}

class single_inherit
{
public static void main(String a[])
{
radha m = new radha();
m.get(520,22000);
m.show1();
}
}

Program to Implement the Basic Functionality of a Calculator using Switch

Program to Implement the Basic Functionality of a Calculator
using Switch
import java.io.DataInputStream;
class Cal
{
public static void main(String args[])
{
DataInputStream pt=new DataInputStream(System.in);
int x,y,z,ch;
try
{
System.out.println("Enter Value of X:");
x = Integer.parseInt(pt.readLine());
System.out.println("Enter Value of Y:");
y = Integer.parseInt(pt.readLine());
System.out.println("1.Addition\n2.Subtraction
\n3.Multiplication\n4.Division");
System.out.println("Enter ur choice:");
ch = Integer.parseInt(pt.readLine());
switch(ch)
{
case 1:
z = x + y;
System.out.println("The Addition is:"+z);
break;
case 2:
z = x - y;
System.out.println("The Subtraction
is:"+z);
break;

case 3:
z = x * y;
System.out.println("The Multiplication
is:"+z);
break;
case 4:
z = x / y;
System.out.println("The Division is:"+z);
break;
default:
System.out.println("Sorry Try
Again.........");
break;
}
}
catch(Exception e)
{
System.out.println("x.getmessage()");
}
}
}

Program to Implement Overriding of Methods

 Program to Implement Overriding of Methods
class bca
{
int d;
void get(int x)
{
d = x;
}
void display()
{
System.out.println("Bca = " + d);
}
}
class mca extends bca
{
int y;
mca(int m, int y)
{
get(m);
this.y = y;
}
void display()
{
System.out.println("Bca = " + d);
System.out.println("mca y= " + y);
}
}

class override
{
public static void main(String a[])
{
mca m = new mca(100,200);
m.display();
}
}

java Program to Implement Overloading of Methods

 Program to Implement Overloading of Methods
class prnt
{
int a, a1, s, s1;
void show()
{
System.out.println("Father name: Mr.Roshan lal");
System.out.println("Mother Name: Mrs. Madhu Gupta") ;
}
}
class radha extends prnt
{
void get(int y)
{
a = 19;
s = y;
}
void show1()
{
System.out.println("\nstd name:Radha Garg");
System.out.println("age:" + a);
System.out.println("salary:" + s);
}
}
class money extends radha
{
void get(int x1,int y1)
{
a1 = x1;
s1 = y1;
}

void show2()
{
System.out.println("\nstd name:Money Garg");
System.out.println("age:" + a1);
System.out.println("salary:" + s1);
}
void shows()
{
show();
show1();
show2();
}
}
class overloading
{
public static void main(String z[])
{
money m = new money();
m.get(20,30000);
m.get(25000);
m.shows();
}
}

java Program to Implement Multithreading

Program to Implement Multithreading
import java.lang.*;
class aa extends Thread
{
public void run()
{
for(int i=0;i<4;i++)
{
try
{
if(i == 3)
{
sleep(4000);
}
}
catch(Exception x)
{ }
System.out.println(i);
}
System.out.println(" i finished ");
}
}
class bb extends Thread
{
public void run()
{
for(int i=0; i<4; i++)
{
System.out.println(i);
}
System.out.println(" ii finished ");
}
}

class cc extends Thread
{
public void run()
{
for(int i=0; i<4; i++)
{
System.out.println(i);
}
System.out.println(" iii finished ");
}
}
class multi_thread
{
public static void main(String arg[])
{
aa a1 = new aa();
bb b1 = new bb();
cc c1 = new cc();
a1.start();
b1.start();
c1.start();
}
}

java Program to Illustrate the use of Methods of Vector Class

 Program to Illustrate the use of Methods of Vector Class
import java.util.*;
class vctr
{
public static void main(String arg[])
{
Vector list = new Vector();
int l = arg.length;
for(int i=0; i<l; i++)
{
list.addElement(arg[i]);
}
list.insertElementAt("COBOL",2);
int size = list.size();
String lary[ ] = new String[size];
list.copyInto(lary);
System.out.println("List of Languages");
for(int i=0; i<size; i++)
{
System.out.println(lary[i]);
}
}
}

java Program to Illustrate the use of Methods of String Class

Program to Illustrate the use of Methods of String Class
import java.io.*;
class String1
{
public static void main(String arg[])
{
try
{
int n = 5;
int m = 8;
char s = 'n';
String str = new String(" Radha");
String str3 = new String(" Radha ");
String str4;
System.out.println(str.equals(str3));
String str1 = str.toLowerCase();
System.out.println("The String in Lower case:"
+ str1);
String str2 = str1.toUpperCase();
System.out.println("The String in Upper case:"
+ str2);
str4 = str1.trim();
System.out.println("The String after trimming:"
+ str4);
System.out.println("The length of String:"
+ str4.length());
str2 = str1.replace('h','d');
System.out.println("The repalced String" + str2);
System.out.println(str1.equals(str2));
System.out.println("The character at position 3:"
+ str2.charAt(3));System.out.println("The substring is:"
+ str2.substring(n));
System.out.println("The substring is:"+ str2.substring(n,m));
System.out.println("The Index of O:"+ str2.indexOf(s));
}
catch(Exception s)
{
System.out.println(s.getMessage());
}
}
}

java Program to Illustrate the use of Methods of StringBuffer Class

 Program to Illustrate the use of Methods of StringBuffer Class

import java.io.*;
import java.lang.*;
class Stringb
{
public static void main(String args[])
{
try
{
StringBuffer str=new StringBuffer("Radha Garg");
System.out.println("\n1.Length\n2.Capacity
\n3.Setlength\n4.Charat\n5.Setcharat
\n6.Append\n7.Deletecharat\n8.Substring
\n9.Substring1\n10.Insert\n11.Reverse");
System.out.println("Enter ur chioce");
DataInputStream ds = new DataInputStream(System.in);
int ch = Integer.parseInt(ds.readLine());
switch(ch)
{
case 1:
System.out.println("The length of the
string is:" + str.length());
break;
case 2:
System.out.println("The capacity of
String:" + str.capacity());
break;
case 3:
str.setLength(15);
System.out.println("Set length of String:"
+ str.length());
break;
case 4:
System.out.println("The character at 6th
position:" + str.charAt(5));
break;
case 5:
str.setCharAt(2,'u');
System.out.println("The string after
setting position is:" +str);
break;
case 6:
System.out.println("The string after
appending:" + str.append(" Sohni"));
break;
case 7:
System.out.println("The string after
deletion:" + str.deleteCharAt(7));
break;
case 8:
System.out.println("The substring is:" +
str.substring(2));
break;
case 9:
System.out.println("The subsstring2 is:" +
str.substring(3,8));
break;
case 10:
System.out.println(" The string after
insertion is:" + str.insert(6,'m'));
break;
case 11:
System.out.println("The string after
reverse is:" + str.reverse());
}
}
catch(Exception s)
{
System.out.println(s.getMessage());
}
}
}
Output:

JAVA Program to Handle In-built Exceptions

Program to Handle any Three In-built Exceptions
class checkExcept
{
public void add()
{
try
{
int y = 20,z = 0;
int x = y/z;
System.out.println(x);
System.out.println("working");
}
catch(ArithmeticException a)
{
System.out.println("error");
}
catch(SecurityException a2)
{
System.out.println("error");
}
catch(ArrayStoreException a1)
{ }
catch(Exception x)
{
System.out.println(x.getMessage());
}
finally
{
System.out.println("finaly");
}
}

public static void main(String a[])
{
checkExcept c = new checkExcept();
c.add();
}
}

Java Program to Find the Sum of the Digits of a Number

Program to Find the Sum of the Digits of a Number
import java.io.*;
class Add
{
void number()
{
try
{
int num,sum=0;
System.out.println("Enter any number:");
DataInputStream dts=new DataInputStream(System.in);
int n=Integer.parseInt(dts.readLine());
while ( n > 0 )
{
num = n % 10;
n = n / 10;
sum = sum + num;
}
System.out.println("The sum of the digits is:"
+sum);
}
catch(Exception s)
{
System.out.println(s.getMessage());
}
}
}

class Digit_add
{
public static void main(String args[])
{
Add a = new Add();
a.number();
}
}