code: protected static ExpressionFactory loadExpressionFactory(String expressionFactoryClassName)
      {
          try
          {
              Class<?> expressionFactoryClass = Class.forName(expressionFactoryClassName);
              return (ExpressionFactory) expressionFactoryClass.newInstance();
          }
          catch (Exception ex)
          {
              if (log.isLoggable(Level.FINE))
              {
                  log.log(Level.FINE, "An error occured while instantiating a new ExpressionFactory. "
                          + "Attempted to load class '" + expressionFactoryClassName + "'.", ex);
              }
          }
  
          return null;
      }
docs: Loads and instantiates the given ExpressionFactory implementation.
  
  @param expressionFactoryClassName the class name of the ExpressionFactory implementation
  @return the newly created ExpressionFactory implementation, or
  <code>null</code>, if an error occurred