title: POI Servlet Check Null no working
body: <p>There are certain result that run in my program and it will be display in excel. Unfortunately the problem i facing was the cell can't set other value if there is null value detected. Error message i get is java null pointer. </p>
  
  <pre><code>  Date invalid_dt=servPerfTracking.getInvalid_d();   
      cell=row.createCell(10);                
              if(cell.getCellType()==cell.CELL_TYPE_BLANK){
  
                  cell.setCellType(Cell.CELL_TYPE_STRING);
                  cell.setCellValue("Apple");
                  log.debug("invalid date is null");
              }else if(cell.getCellType()==cell.CELL_TYPE_STRING){    
  
                  cell=row.createCell(10);
                  cell.setCellValue(invalid_dt);
                  cell.setCellStyle(dataCellStyle);
                  log.debug("invalid date is not equal to null");
              }
  </code></pre>