package demo;


import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;


import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class DemoExcel {

    public static void main(String[] args) throws Exception{
        File excel = new File("C:\Users\Devaditya\Documents\Book1.xlsx");
        FileInputStream fis = null;
        fis = new FileInputStream(excel);
        System.out.println(fis.toString());
        HSSFWorkbook wb = new HSSFWorkbook(fis);
        System.out.println(wb.toString());
        HSSFSheet sh = wb.getSheet("Data");
        System.out.println(sh.toString());
    }

}

Exception in thread "main" java.io.IOException: Invalid header signature; read 0, expected -2226271756974174256
    at org.apache.poi.poifs.storage.HeaderBlockReader.<init>(HeaderBlockReader.java:88)
    at org.apache.poi.poifs.filesystem.POIFSFileSystem.<init>(POIFSFileSystem.java:83)
    at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:210)
    at org.apache.poi.hssf.usermodel.HSSFWorkbook.<init>(HSSFWorkbook.java:191)
    at demo.DemoExcel.main(DemoExcel.java:23)

final Workbook workbook = WorkbookFactory.create(excel);