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Excel File is getting Corrupted while renaming the Existing excel file with Current date and Time?

When I am renaming the existing Excel file using below code, Excel File is getting generated with Current Time Stamp but when I am trying the open the renamed Excel file, I am not able to Open it. It is showing Workbook is Corrupted.
Please Find Out where is the Error in the Below code. Why Excel File is getting Corrupted?
package BrokenLink;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class CreateExcelFile {
public static void main(String[] args)
{
//new File("C:\\Users\\skumari1\\eclipse-workspace\\AlarmTest\\Generics").mkdir();
CreateFileRenameExisting("NewBook.xlsx");
}
//Rename an existing file and create a new file
public static void CreateFileRenameExisting(String filename)
{
//get current project path
String filePath=System.getProperty("user.dir");
//create a new file
File file=new File(filePath+"\\"+filename);
try {
if(!file.exists()) {
Workbook wb1 = new XSSFWorkbook();
FileOutputStream fileOut1 = new FileOutputStream(filename);
wb1.write(fileOut1);
fileOut1.close();
//file.createNewFile();
System.out.println("File is created");
}
else
{
File backupFile=new File(filePath+"\\"+ Validatedate() + file.getName());
System.out.println("File already exist and backup file is created");
file.renameTo(backupFile);
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static String Validatedate() {
SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH_mm_ss");
Date date = new Date();
String date1= dateFormat.format(date);
// System.out.println("Current date and time is " +date1);
return date1;
}
}
Thank you in advance.

I think you should add workbook code in else part too.
As you are simply renaming the file with File object may be the reason your excel is getting corrupted.
Add Workbook code in else part and also close your workbook instance once all operations are done.

Extract Paragraph from Word Document Using Apache POI

I have an word document
Docx file
As you can see in the word document there are a number of questions with Bullet Points. Right now I am trying to extract each paragraph from the file using apache POI. Here is my current code
public static String readDocxFile(String fileName) {
try {
File file = new File(fileName);
FileInputStream fis = new FileInputStream(file.getAbsolutePath());
XWPFDocument document = new XWPFDocument(fis);
List<XWPFParagraph> paragraphs = document.getParagraphs();
String whole = "";
for (XWPFParagraph para : paragraphs) {
System.out.println(para.getText());
whole += "\n" + para.getText();
}
fis.close();
document.close();
return whole;
} catch (Exception e) {
e.printStackTrace();
return "";
}
}
The problem with above method is that it is printing each line instead of paragraphs. Also the bullet points are also gone from extracted whole string. The whole is returned a plain string.
Can anyone explain what I am doing wrong. Also please suggest if you have a better idea to solve it.

Above code is correct and I ran your code on my system that giving each and every paragraphs , I think problem with writting content on docx file whenever I wrote content in bullet points and uses 'enter' key than that breaks my current bullet points and above code make that breaked-line as saparate paragraph.
I am writting below code sample may be It's useful for you take a look here I am using Set datastructure for ignoring duplicate questions from docx .
Dependency of apache poi is below
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.7</version>
</dependency>
Code Sample :
package com;
import java.io.File;
import java.io.FileInputStream;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.xwpf.usermodel.XWPFParagraph;
import org.springframework.util.ObjectUtils;
public class App {
public static void main(String...strings) throws Exception{
Set<String> bulletPoints = fileExtractor();
bulletPoints.forEach(point -> {
System.out.println(point);
});
}
public static Set<String> fileExtractor() throws Exception{
FileInputStream fis = null;
try {
Set<String> bulletPoints = new HashSet<>();
File file = new File("/home/deskuser/Documents/query.docx");
fis = new FileInputStream(file.getAbsolutePath());
XWPFDocument document = new XWPFDocument(fis);
List<XWPFParagraph> paragraphs = document.getParagraphs();
paragraphs.forEach(para -> {
System.out.println(para.getText());
if(!ObjectUtils.isEmpty(para.getText())){
bulletPoints.add(para.getText());
}
});
fis.close();
return bulletPoints;
} catch (Exception e) {
e.printStackTrace();
throw new Exception("error while extracting file.", e);
}finally{
if(!ObjectUtils.isEmpty(fis)){
fis.close();
}
}
}
}

I couldn't find which version of apache POI you are using. If it's the latest version (3.17), the XWPFParagraph object used in your code has a getNumFmt() method. From the apache poi documentation (https://poi.apache.org/apidocs/org/apache/poi/xwpf/usermodel/XWPFParagraph.html) this method will return the string "bullet" if the paragraph starts with a bullet. So regarding the second point of your question (what happens to the bullets), you can resolve with something like the following:
public class TestPoi {
private static final String BULLET = "•";
private static final String NEWLINE = "\n";
public static void main(String...args) {
String test = readDocxFile("/home/william/Downloads/anesthesia.docx");
System.out.println(test);
}
public static String readDocxFile(String fileName) {
try {
File file = new File(fileName);
FileInputStream fis = new FileInputStream(file.getAbsolutePath());
XWPFDocument document = new XWPFDocument(fis);
List<XWPFParagraph> paragraphs = document.getParagraphs();
StringBuilder whole = new StringBuilder();
for (XWPFParagraph para : paragraphs) {
if ("bullet".equals(para.getNumFmt())) {
whole.append(BULLET);
}
whole.append(para.getText());
whole.append(NEWLINE);
}
fis.close();
document.close();
return whole.toString();
} catch (Exception e) {
e.printStackTrace();
return "";
}
}
}
Regarding your first point, what is the expected output? I ran your code with the provided docx and apart from the missing bullets you mentioned, it looked okay stepping through with the debugger.

Error creating an Excel file with Apache POI library.

Here is my code:
import org.apache.poi.hslf.HSLFSlideShow;
import org.apache.poi.hslf.model.Slide;
import org.apache.poi.hslf.usermodel.SlideShow;
import java.io.*;
public class CreateNewPresentation
{
public static void main(args[])
{
try
{
SlideShow slideShow = new SlideShow();
Slide slide = slideShow.createSlide();
FileOutputStream out = new
FileOutputStream("slideshow.ppt");
slideShow.write(out);
System.out.println("File Created...");
out.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
The issue is that it does not recognise org.apache.poi package.
How can I make it work?

If you are using netbeans, refer this for setting classpath.
If you want to set classpath from command line refer this

Extracting tar.gz using java error

I am trying to extract an archive .tar.gz using java and I am getting Directory error that I do not seem to understand. Please help. I got this sample code from https://forums.oracle.com/forums/thread.jspa?threadID=2065236
package untargz;
import java.io.*;
import com.ice.tar.*;
import javax.activation.*;
import java.util.zip.GZIPInputStream;
/**
*
* #author stanleymungai
*/
public class Untargz {
public static InputStream getInputStream(String tarFileName) throws Exception{
if(tarFileName.substring(tarFileName.lastIndexOf(".") + 1, tarFileName.lastIndexOf(".") + 3).equalsIgnoreCase("gz")){
System.out.println("Creating an GZIPInputStream for the file");
return new GZIPInputStream(new FileInputStream(new File(tarFileName)));
}else{
System.out.println("Creating an InputStream for the file");
return new FileInputStream(new File(tarFileName));
}
}
private static void untar(InputStream in, String untarDir) throws IOException {
System.out.println("Reading TarInputStream... ");
TarInputStream tin = new TarInputStream(in);
TarEntry tarEntry = tin.getNextEntry();
if(new File(untarDir).exists()){
while (tarEntry != null){
File destPath = new File(untarDir + File.separatorChar + tarEntry.getName());
System.out.println("Processing " + destPath.getAbsoluteFile());
if(!tarEntry.isDirectory()){
FileOutputStream fout = new FileOutputStream(destPath);
tin.copyEntryContents(fout);
fout.close();
}else{
destPath.mkdir();
}
tarEntry = tin.getNextEntry();
}
tin.close();
}else{
System.out.println("That destination directory doesn't exist! " + untarDir);
}
}
private void run(){
try {
String strSourceFile = "C:/AskulInstaller/pid.tar.gz";
String strDest = "C:/AskulInstaller/Extracted Files";
InputStream in = getInputStream(strSourceFile);
untar(in, strDest);
}catch(Exception e) {
e.printStackTrace();
System.out.println(e.getMessage());
}
}
public static void main(String[] args) {
new Untargz().run();
}
}
Once I run this piece of code, this is My Output;
Creating an GZIPInputStream for the file
Reading TarInputStream...
That destination directory doesn't exist! C:/AskulInstaller/Extracted Files
BUILD SUCCESSFUL (total time: 0 seconds)
When I Manually Create the destination Directory C:/AskulInstaller/Extracted Files
I get this Error Output;
Creating an GZIPInputStream for the file
Reading TarInputStream...
Processing C:\AskulInstaller\Extracted Files\AskulInstaller\pid\Askul Logs\DbLayer_AskulMain_10_Apr_2013_07_44.log
java.io.FileNotFoundException: C:\AskulInstaller\Extracted Files\AskulInstaller\pid\Askul Logs\DbLayer_AskulMain_10_Apr_2013_07_44.log (The system cannot find the path specified)
C:\AskulInstaller\Extracted Files\AskulInstaller\pid\Askul Logs\DbLayer_AskulMain_10_Apr_2013_07_44.log (The system cannot find the path specified)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:212)
at java.io.FileOutputStream.<init>(FileOutputStream.java:165)
at untargz.Untargz.untar(Untargz.java:37)
at untargz.Untargz.run(Untargz.java:55)
at untargz.Untargz.main(Untargz.java:64)
Is there a way I am supposed to place My directories so that the extraction Happens or what exactly is My Mistake?

If the tar file contains an entry for a file foo/bar.txt but doesn't contain a previous directory entry for foo/ then your code will be trying to create a file in a directory that doesn't exist. Try adding
destFile.getParentFile().mkdirs();
just before you create the FileOutputStream.
Alternatively, if you don't mind your code depending on Ant as a library then you can delegate the whole unpacking process to an Ant task rather than doing it by hand. Something like this (not fully tested):
Project p = new Project();
Untar ut = new Untar();
ut.setProject(p);
ut.setSrc(tarFile);
if(tarFile.getName().endsWith(".gz")) {
ut.setCompression((UntarCompressionMethod)EnumeratedAttribute.getInstance(UntarCompressionMethod.class, "gzip"));
}
ut.setDest(destDir);
ut.perform();

Writing to .xlsx using java. BiffViewer error occurs

jars I have used : dom4j poi-3.8.jar poi-ooxml-3.8.jar poi-ooxml-schemas-3.8.jar xbean.jar
The code :
package org.capgemini.ui;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class XSSFWorkBookWriter {
public void writeWorkBook(Vector table) throws Exception {
XSSFWorkbook workBook = new XSSFWorkbook();
XSSFSheet sheet = workBook.createSheet();
table=new Vector();
table.add(new String("Howdy"));
table.add(new java.sql.Date(2012,06,20));
table.add(new Double(13.35D));
table.add(new String("Fine"));
table.add(new java.sql.Date(2012,06,20));
table.add(new Double(13.38D));
Iterator rows=table.iterator();
Enumeration rowsOfVector=table.elements();
int totalNoOfRows=table.size()/2;
int currentRow=0;
while (rows.hasNext () && currentRow<totalNoOfRows){
XSSFRow row = sheet.createRow(currentRow++);
for (int i = 0; i < 3; i++) {
XSSFCell cell=row.createCell(i);
Object val=rows.next();
if( val instanceof String){
cell.setCellValue(val.toString());
}
else if(val instanceof Date){
cell.setCellValue((java.sql.Date)val);
}
else if(val instanceof Double){
cell.setCellValue((Double)val);
}
}
}
FileOutputStream outPutStream = null;
try {
outPutStream = new FileOutputStream("D:/Try.xlsx");
workBook.write(outPutStream);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (outPutStream != null) {
try {
outPutStream.flush();
outPutStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public static void main(String[] args) {
XSSFWorkBookWriter bookWriter=new XSSFWorkBookWriter();
try {
bookWriter.writeWorkBook(new Vector());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
ERROR ::
org.apache.poi.hssf.dev.BiffViewer$CommandParseException: Biff viewer needs a filename
at org.apache.poi.hssf.dev.BiffViewer$CommandArgs.parse(BiffViewer.java:333)
at org.apache.poi.hssf.dev.BiffViewer.main(BiffViewer.java:386)

BiffViewer is part of HSSF, which only works with the older .xls files (OLE2 based). You're generating a .xlsx file with XSSF, which is a different low level format.
If you really want to use BiffViewer (not sure why, it's normally only used with debugging, but still), then you'll need to change your XSSF code to be HSSF code. Otherwise, if you did mean to be using XSSF to generate a .xlsx file, then you can't use the HSSF debugging tools. If you want to know what's in your .xlsx file, unzip it (.xlsx is a zip of xml files) and view the XML.