Java program to Merge two Excel sheets

This program has been taken from the below link and enhanced for easy use and easy understanding. This program is working 100% and the result is accurate.
Jars used: poi.jar

https://coderanch.com/t/614715/java/merge-excel-files - Thanks for the program

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.CellRangeAddress;


@SuppressWarnings("deprecation")
public class MSExcel {
 public static void main(String args[]) throws FileNotFoundException{
  MSExcel mslobj = new MSExcel();
  mslobj.readExcel();
 }

 private void readExcel() {
  // TODO Auto-generated method stub
  try {
   String FilePath = "C:\\Users\\test.xls";
   String FilePath1 = "C:\\Users\\test1.xls";
   FileInputStream fis = new FileInputStream(FilePath);
   FileInputStream fis1 = new FileInputStream(FilePath1);
   HSSFWorkbook workbook = new HSSFWorkbook(fis);
   HSSFSheet sheet = workbook.getSheet(“sheet”);
 
   HSSFWorkbook wb = new HSSFWorkbook(fis1);
   //Workbook wb = new XSSFWorkbook();
   HSSFSheet sheet1 = wb.getSheet(“sheet1”);
   copySheets(sheet1, sheet);
 
   FileOutputStream outfile = new FileOutputStream("C:\\Users\\test1.xls");
   wb.write(outfile);
   outfile.close();
  } catch (FileNotFoundException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
 
  public static void copySheets(HSSFSheet newSheet, HSSFSheet sheet){
    copySheets(newSheet, sheet, true);
  }
     
       public static void copySheets(HSSFSheet newSheet, HSSFSheet sheet, boolean copyStyle){
           int maxColumnNum = 0;
           Map<Integer, HSSFCellStyle> styleMap = (copyStyle) ? new HashMap<Integer, HSSFCellStyle>() : null;
           for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {
               HSSFRow srcRow = sheet.getRow(i);
               HSSFRow destRow = newSheet.createRow(i);
               if (srcRow != null) {
                   MSExcel.copyRow(sheet, newSheet, srcRow, destRow, styleMap);
                   if (srcRow.getLastCellNum() > maxColumnNum) {
                       maxColumnNum = srcRow.getLastCellNum();
                   }
               }
           }
           for (int i = 0; i <= maxColumnNum; i++) {
               newSheet.setColumnWidth(i, sheet.getColumnWidth(i));
           }
       }
 
       public static void copyRow(HSSFSheet srcSheet, HSSFSheet destSheet, HSSFRow srcRow, HSSFRow destRow, Map<Integer, HSSFCellStyle> styleMap) {
           @SuppressWarnings("deprecation")
     Set<CellRangeAddress> mergedRegions = new TreeSet<CellRangeAddress>();
           destRow.setHeight(srcRow.getHeight());
           for (int j = srcRow.getFirstCellNum(); j <= srcRow.getLastCellNum(); j++) {
               HSSFCell oldCell = srcRow.getCell(j);
               HSSFCell newCell = destRow.getCell(j);
               if (oldCell != null) {
                   if (newCell == null) {
                       newCell = destRow.createCell(j);
                   }
                   copyCell(oldCell, newCell, styleMap);
                   CellRangeAddress mergedRegion = getMergedRegion(srcSheet, srcRow.getRowNum(), (short)oldCell.getColumnIndex());
                   if (mergedRegion != null) {
                       CellRangeAddress newMergedRegion = new CellRangeAddress(mergedRegion.getFirstRow(), mergedRegion.getFirstColumn(), mergedRegion.getLastRow(), mergedRegion.getLastColumn());
                       if (isNewMergedRegion(newMergedRegion, mergedRegions)) {
                           mergedRegions.add(newMergedRegion);
                           destSheet.addMergedRegion(newMergedRegion);
                       }
                   }
               }
           }
         
       }
     
       public static void copyCell(HSSFCell oldCell, HSSFCell newCell, Map<Integer, HSSFCellStyle> styleMap) {
           if(styleMap != null) {
               if(oldCell.getSheet().getWorkbook() == newCell.getSheet().getWorkbook()){
                   newCell.setCellStyle(oldCell.getCellStyle());
               } else{
                   int stHashCode = oldCell.getCellStyle().hashCode();
                   HSSFCellStyle newCellStyle = styleMap.get(stHashCode);
                   if(newCellStyle == null){
                       newCellStyle = newCell.getSheet().getWorkbook().createCellStyle();
                       newCellStyle.cloneStyleFrom(oldCell.getCellStyle());
                       styleMap.put(stHashCode, newCellStyle);
                   }
                   newCell.setCellStyle(newCellStyle);
               }
           }
           switch(oldCell.getCellType()) {
               case HSSFCell.CELL_TYPE_STRING:
                   newCell.setCellValue(oldCell.getStringCellValue());
                   break;
               case HSSFCell.CELL_TYPE_NUMERIC:
                   newCell.setCellValue(oldCell.getNumericCellValue());
                   break;
               case HSSFCell.CELL_TYPE_BLANK:
                   newCell.setCellType(HSSFCell.CELL_TYPE_BLANK);
                   break;
               case HSSFCell.CELL_TYPE_BOOLEAN:
                   newCell.setCellValue(oldCell.getBooleanCellValue());
                   break;
               case HSSFCell.CELL_TYPE_ERROR:
                   newCell.setCellErrorValue(oldCell.getErrorCellValue());
                   break;
               case HSSFCell.CELL_TYPE_FORMULA:
                   newCell.setCellFormula(oldCell.getCellFormula());
                   break;
               default:
                   break;
           }
         
       }
     
       public static CellRangeAddress getMergedRegion(HSSFSheet sheet, int rowNum, short cellNum) {
           for (int i = 0; i < sheet.getNumMergedRegions(); i++) {
               CellRangeAddress merged = (CellRangeAddress) sheet.getMergedRegion(i);
               if (merged.isInRange(rowNum, cellNum)) {
                   return merged;
               }
           }
           return null;
       }
 
       private static boolean isNewMergedRegion(CellRangeAddress newMergedRegion, Collection<CellRangeAddress> mergedRegions) {
           return !mergedRegions.contains(newMergedRegion);
       }
     
 }

Simple Java program to find Prime number

This program has made simple for better understanding of beginners.

import java.util.Scanner;

public class PrimeNumber {

public static void main(String args[]){

System.out.println("Enter the number: ");

//To receive input from users

Scanner s = new Scanner(System.in);

int num = s.nextInt();

s.close();

//Logic to detect the prime number

for(int i=2; i<num; i++){

int temp = num%i;

if (temp == 0){

System.out.println("This is not a prime number.");

break;

} 

else{

if (i == (num-1)){

System.out.println("This is a prime number.");

}

}

} 

}

}

Output:

Enter the number: 

21

This is not a prime number.

Enter the number: 

3

This is a prime number.

Simple Java program for Odd or Even

This program has been simplified for beginners to find the given number is Odd or Even.

import java.util.Scanner;

public class OddrEven {

public static void main(String args[]){

//To get the input number from user

System.out.println("Enter the number: ");

Scanner sc = new Scanner(System.in);

int inp = sc.nextInt();

sc.close();

//Simple logic to check the number is Odd or Even

int temp = inp % 2;

if (temp == 0){

System.out.println("This is a even number.");

}else{

System.out.println("This is a odd number.");

}

}

}

Output:

Enter the number: 

45

This is a odd number.

Enter the number: 

22

This is a even number.

Amazon interview question - To find the first repeated character in a String

Question: How to find the first repeated character in a String?

The below java program has been written in easy way to make the beginners understand how easy the way of coding is and how easily a concept can be achieved through programming.

import java.util.Scanner;

public class StrRepeat {

public static void main(String args[]){

//Get the string to check the non repreated character

System.out.println("Enter the String: ");

Scanner s = new Scanner(System.in);

String str = s.nextLine();

char fin = checkLetter(str);

System.out.println("The character is: " + fin);

s.close();

}

//To check each individual char for non repeated

private static char checkLetter(String str) {

// TODO Auto-generated method stub

//To split the string to character

char[] ary = str.toCharArray();

char val = 0;

//To get the length of character

int len = ary.length;

char temp[] = new char[len];

for (int i=0; i<len; i++){

for (int j=0; j<len; j++){

if (j!= i){

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

temp[i] = '$';

}

}

}

}

for (int k = 0; k< len; k++){

if (temp[k] == '$' ){

val = ary[k];

break;

}

}

return val;

}

}

Output:

Enter the String: lmadam

The character is: m

Amazon interview question - Find first non repeated character in a string

Question: how to find the first non-repeated character in a String?

The below Java program has been optimised and written easy for understanding.

import java.util.Scanner;

public class StrRepeat {

           public static void main(String args[]){

          //Get the string to check the non repreated character

          System.out.println("Enter the String: ");

          Scanner s = new Scanner(System.in);

          String str = s.nextLine();

          char fin = checkLetter(str);

          System.out.println("The character is: " + fin);

          s.close();

}

//To check each individual char for non repeated

private static char checkLetter(String str) {

// TODO Auto-generated method stub

           //To split the string to character

           char[] ary = str.toCharArray(); 

           char val = 0;

           //To get the length of character

           int len = ary.length;

           char temp[] = new char[len];

           for (int i=0; i<len; i++){

                 for (int j=0; j<len; j++){

                    if (j!= i){

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

                                   temp[i] = '$';

                         }

                   }

            }

}

for (int k = 0; k< len; k++){

if (temp[k] != '$' ){

val = ary[k];

break;

}

}

return val;

}

}

Output:

Enter the String: madam

The character is: d

Simple Java program for Palindrome

This program is simplified for easy understanding using the StringBuilder with reverse function in java.

import java.util.Scanner;

public class Palindrome {

public static void main(String args[]){

//Get the string to check 

System.out.println("Enter the string: ");

Scanner sc = new Scanner(System.in);

String inp = sc.nextLine();

sc.close();

//String to string builder to store in heap

StringBuilder sb = new StringBuilder();

sb.append(inp);

//Reverse function over the string 

sb = sb.reverse();

String temp = sb.toString();

//compare to check Palindrome

if (inp.equals(temp)){

System.out.println("The given string is a Palindrome.");

}else{

System.out.println("The given string is not a Palindrome.");

}

}

}

Output:

Enter the string: madam

The given string is a Palindrome.

Enter the string: Rajesh

The given string is not a Palindrome.