Thread: NoClassDefFoundError while reading Excel File (Apache POI 5.0.0)

I am trying to read an excel file into a JTable. I gotten this NoClassDefFoundError at this line:

XSSFWorkbook excelJTableImport = new XSSFWorkbook(excelBIS);

I'm using Apache POI 5.0.0.

Code of table definition:

		table = new JTable();
		scrollPane.setViewportView(table);
		table.setModel(new DefaultTableModel(
			new Object[][] {
			},
			new String[] {
				"User Name", "Record Date", "Final Score", "Oil Average", "Hydration Average", "Melanin Average", "Oxygen Average", "Redness Average"
			}
		) {
			Class[] columnTypes = new Class[] {
				String.class, String.class, Integer.class, Integer.class, Integer.class, Integer.class, Integer.class, Integer.class
			};
			public Class getColumnClass(int columnIndex) {
				return columnTypes[columnIndex];
			}
		});

Code when browse button is selected:

		JButton btnBrowse = new JButton("Browse File");
 
		btnBrowse.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				//Definitions
				 DefaultTableModel model=null;
	        	    String userName = "";
	        	    String recordDate = "";
	        	    Integer finalScore = 0;
	        	    Integer oilAverage = 0;
	        	    Integer hydrationAverage = 0;
	        	    Integer melaninAverage = 0;
	        	    Integer oxygenAverage = 0;
 
				//=========Action here==========
				File excelFile;
		        FileInputStream excelFIS = null;
		        BufferedInputStream excelBIS = null;
		        XSSFWorkbook workbook=null;
 
		        //Default Path
		        String defaultPath = "C:\\";
		        JFileChooser fileChooser=new JFileChooser(defaultPath);
		        int excelChooser=fileChooser.showOpenDialog(null);
 
		        //Open Button Clicked
		        if(excelChooser==JFileChooser.APPROVE_OPTION)
		        {
		        	try
		        	{
		        		excelFile=fileChooser.getSelectedFile();
			        	excelFIS=new FileInputStream(excelFile);
			        	excelBIS=new BufferedInputStream(excelFIS);
 
			        	workbook = new XSSFWorkbook(excelBIS);
			        	XSSFSheet excelSheet = workbook.getSheetAt(0);
 
			        	//Loop through excel columns and rows
			        	for(int row=0;row<10;row++)
			        	{
 
 
 
			        		XSSFRow excelRow=excelSheet.getRow(row);
 
			        		XSSFCell excelName = excelRow.getCell(0);
		                    XSSFCell excelDate = excelRow.getCell(1);
		                    XSSFCell excelScore = excelRow.getCell(2);
		                    XSSFCell excelOil = excelRow.getCell(3);
		                    XSSFCell excelHydration = excelRow.getCell(4);
		                    XSSFCell excelMelanin = excelRow.getCell(5);
		                    XSSFCell excelOxygen = excelRow.getCell(6);
		                    XSSFCell excelRedness = excelRow.getCell(7);
 
		                    model.addRow(new Object[]{excelName, excelDate, excelScore, excelOil, excelHydration,excelMelanin,excelOxygen,excelRedness});
			        	}
		        	}catch(FileNotFoundException ex)
		        	{
		        		JOptionPane.showMessageDialog(null, ex.getMessage());
		        	}catch(IOException ex)
		        	{
		        		JOptionPane.showMessageDialog(null, ex.getMessage());
		        	}finally {
		                try {
		                    if (excelFIS != null) {
		                        excelFIS.close();
		                    }
		                    if (excelBIS != null) {
		                        excelBIS.close();
		                    }
		                    if (workbook != null) {
		                    	workbook.close();
		                    }
		                } catch (IOException iOException) {
		                    JOptionPane.showMessageDialog(null, iOException.getMessage());
		                }
		            }
 
		        }
			}
		});

Additionally, I got a warning at this line

 model.addRow(new Object[]{excelName, excelDate, excelScore, excelOil, excelHydration,excelMelanin,excelOxygen,excelRedness});

that model can only be null at this location.

What did I do wrong that caused me the warning and error? How do I fix this?
Help is appreciated!