Check out example codes for "open an existing excel file in java apache poi". It will help you in understanding the concepts better.

Code Example 1

import org.apache.poi.xssf.usermodel.XSSFWorkbook; 
public class GFG { 
    public static void main(String args[]) throws Exception 
        // Create a file object 
        // for the path of existing Excel file 
        // Give the path of the file as parameter 
        // from where file is to be read 
        File file = new File("Geeks.xlsx"); 
        // Create a FileInputStream object 
        // for getting the information of the file 
        FileInputStream fip = new FileInputStream(file); 
        // Getting the workbook instance for XLSX file 
        XSSFWorkbook workbook = new XSSFWorkbook(fIP); 
        // Ensure if file exist or not 
        if (file.isFile() && file.exists()) { 
            System.out.println("Geeks.xlsx open"); 
        else { 
            System.out.println("Geeks.xlsx either not exist"
                               + " or can't open"); 

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