title: simple JXLS / Apache POI example fails
body: <p>I have no idea way I get this error. The code is from JXLS own example and the Jars are downloaded from there page.</p>
  
  <p>Error code:</p>
  
  <pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/poi/ss/usermodel/Workbook
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:264)
      at org.jxls.util.TransformerFactory.loadPoiTransformer(TransformerFactory.java:85)
      at org.jxls.util.TransformerFactory.getTransformerClass(TransformerFactory.java:69)
      at org.jxls.util.TransformerFactory.createTransformer(TransformerFactory.java:27)
      at org.jxls.util.JxlsHelper.createTransformer(JxlsHelper.java:250)
      at org.jxls.util.JxlsHelper.processTemplate(JxlsHelper.java:108)
      at test_excel.ObjectCollectionDemo.main(ObjectCollectionDemo.java:32)
  
  Caused by: java.lang.ClassNotFoundException: org.apache.poi.ss.usermodel.Workbook
      at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
  ... 8 more
  </code></pre>
  
  <p>Referenced Libraries:<br></p>
  
  <p>/slf4j-1.7.25/slf4j-api-1.7.25.jar<br>
  /slf4j-1.7.25/slf4j-jdk14-1.7.25.jar<br>
  /jxls-2.4.1 2/dist/jxls-reader-2.0.3.jar<br>
  /jxls-2.4.1 2/dist/jxls-poi-1.0.13.jar<br>
  /xls-2.4.1 2/dist/jxls-jexcel-1.0.6.jar<br>
  /jxls-2.4.1 2/dist/jxls-2.4.1.jar<br></p>
  
  <p>Main code:</p>
  
  <pre><code>package test_excel;
  
  import org.jxls.common.Context;
  import org.jxls.util.JxlsHelper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.text.ParseException; 
  import java.text.SimpleDateFormat;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  
  
  public class ObjectCollectionDemo {
      private static Logger logger = LoggerFactory.getLogger(ObjectCollectionDemo.class);
  
      public static void main(String[] args) throws ParseException, IOException {
          logger.info("Running Object Collection demo");
          List&lt;Employee&gt; employees = generateSampleEmployeeData();
  
          try(InputStream is = ObjectCollectionDemo.class.getResourceAsStream("object_collection_template.xls")) {
              try (OutputStream os = new FileOutputStream("object_collection_output.xls")) {
                  Context context = new Context();
                  context.putVar("employees", employees);
  
                  logger.info("OK so far...");
  
                  JxlsHelper.getInstance().processTemplate(is, os, context);
              }
          }
      }  
  
      public static List&lt;Employee&gt; generateSampleEmployeeData() throws ParseException {
          List&lt;Employee&gt; employees = new ArrayList&lt;Employee&gt;();
          SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MMM-dd", Locale.US);
  
          employees.add( new Employee("Elsa", dateFormat.parse("1970-Jul-10"), 1500, 0.15) );
          employees.add( new Employee("Oleg", dateFormat.parse("1973-Apr-30"), 2300, 0.25) );
          employees.add( new Employee("Neil", dateFormat.parse("1975-Oct-05"), 2500, 0.00) );
          employees.add( new Employee("Maria", dateFormat.parse("1978-Jan-07"), 1700, 0.15) );
          employees.add( new Employee("John", dateFormat.parse("1969-May-30"), 2800, 0.20) );
  
          return employees;
      }
  }
  </code></pre>