title: XSSFWorkbook Constructor from file getting stuck on import
body: <p>I recently attempted to rename my project in Eclipse using refactoring, and when I did I ran into many errors. I think I resolved all of them, but now my program is getting stuck while reading in a .xlsx file. </p>
  
  <pre><code>File file = new File("C://Users/user1/ExcelFile.xlsx");
  
  if(!file.getName().endsWith("xlsx")) {
          JOptionPane.showMessageDialog(null, 
          "Please select an Excel file (.xlsx)",
                      "Error", JOptionPane.ERROR_MESSAGE);
  } else {
  
      XSSFWorkbook workbook = null;
      try {
          // Find the workbook instance for XLSX file
          workbook = new XSSFWorkbook(file);
      } catch (IOException e) {
          Logger.getLogger(
                  XLSXHandler.class.
                  getName()).log(Level.SEVERE, null, e);;
      }
      // Return first sheet from the XLSX workbook
      XSSFSheet mySheet = workbook.getSheetAt(0);
  
      // reading sheet into taskList
      tasks = readInTasks(mySheet);
  }
  </code></pre>
  
  <p>The problem area seeems to be in the "workbook = new XSSFWorkbook(file);" line because in the debugger, workbook is filled with null values. In my build path, I have included the following .jar files:</p>
  
  <ul>
  <li>poi-3.15-beta1.jar</li>
  <li>poi-ooxml-3.15-beta1.jar</li>
  <li>poi-ooxml-schemas-3.15-beta1.jar</li>
  <li>xmlbeans-2.6.0.jar</li>
  <li>commons-codec-1.10.jar</li>
  <li>jxl.jar</li>
  <li>stax-api-1.0.1.jar</li>
  </ul>
  
  <p>Any ideas?</p>