title: Can't create JexlEngine object
body: <p>I write the following class:</p>
  
  <pre><code>import org.apache.commons.jexl2.*;
  
  public class NelderMead {
      // контсанты
      private static int      M = 3;
      private static double   E = 0.005;
      private static double   A = 1.000;
      private static double   B = 0.500;
      private static double   Y = 2.000;
  
      // переменные
      private JexlEngine jexl = new JexlEngine();
      private Expression func;
      private String funcString = "";
      private MapContext[] iterations;
  
      public NelderMead(){
          this.jexl = new JexlEngine();
      }
  
      public NelderMead(String funcString){
          this.jexl = new JexlEngine();
          this.setFunc(funcString);
      }
  
  
      public void setFunc(String funcString){
          this.funcString = funcString;
          this.func = this.jexl.createExpression(funcString);
      }
  
      public double funcEval(MapContext args){
          return (Double) this.func.evaluate(args);
      }
  
      public boolean checkCriterian(){
          return true;
      }
  }
  </code></pre>
  
  <p>But the I create object of this class I have the foolowing error:</p>
  
  <pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
      at org.apache.commons.jexl2.JexlEngine$UberspectHolder.&lt;clinit&gt;(JexlEngine.java:121)
      at org.apache.commons.jexl2.JexlEngine.getUberspect(JexlEngine.java:205)
      at org.apache.commons.jexl2.JexlEngine.&lt;init&gt;(JexlEngine.java:182)
      at org.apache.commons.jexl2.JexlEngine.&lt;init&gt;(JexlEngine.java:170)
      at NelderMead.&lt;init&gt;(NelderMead.java:22)
      at Test.main(Test.java:10)
  Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory
      at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
      ... 6 more
  </code></pre>
  
  <p>on first line of the constructor (when create an object of JexlEngine):</p>
  
  <pre><code>public NelderMead(String funcString){
      this.jexl = new JexlEngine();
      this.setFunc(funcString);
  }
  </code></pre>
  
  <p>Could you help me - why this code cause the errors?</p>
  
  <p>PS
  I use .jar file to use this lib.</p>