title: java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.text.StringEscapeUtils
body: <p>I am writing a character filter function, using <code>commons-text-1.6.jar</code>.<br>
  The log function is okay, but then this error shows up:</p>
  
  <pre class="lang-none prettyprint-override"><code>java.lang.NoClassDefFoundError: Could not initialize class org.apache.commons.text.StringEscapeUtils
      cc.openhome.web.EscapeWrapper.getParameter(EscapeWrapper.java:15)
      cc.openhome.controller.Login.doPost(Login.java:30)
      javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
      javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
      org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
      cc.openhome.web.EscapeFilter.doFilter(EscapeFilter.java:16)
  </code></pre>
  
  <p>Code:</p>
  
  <pre><code>package cc.openhome.web;
  
  import org.apache.commons.text.StringEscapeUtils;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletRequestWrappe
  
  public class EscapeWrapper extends HttpServletRequestWrapper {
      public EscapeWrapper(HttpServletRequest req){enter code here
          super(req);
      }
  
      public String getParameter(String name){
          String value = getRequest().getParameter(name);
          return StringEscapeUtils.escapeHtml4(value);
      }
  }
  </code></pre>