title: POI 3.7 java.lang.IncompatibleClassChangeError when instantiating a Font
body: <p>I am getting a java.lang.IncompatibleClassChangeError with the following snippet:</p>
  
  <pre><code>Workbook workbook = new HSSFWorkbook();
  Font arial = workbook.createFont(); // java.lang.IncompatibleClassChangeError thrown here
  </code></pre>
  
  <p>I am using POI 3.7 with WebSphere 7 Portal Server. The same code (and as far as I can tell, the same jars) worked with Netbeans console application. It also seems that the 3.7 jar is the only one in the classpath. The project also uses JasperReports 4.1.2. Can I provide more information?</p>