code: public static boolean isUnifiedELAvailable()
      {
          if (unifiedELAvailable == null)
          {
              try
              {
                  // Check if the UEL classes are available.
                  // If the JSP EL classes are loaded first, UEL will not work
                  // properly, hence it will be disabled.
                  unifiedELAvailable = (
                          Class.forName("javax.el.ValueReference") != null
                       && Class.forName("javax.el.ValueExpression")
                                  .getMethod("getValueReference", ELContext.class) != null
                  );
              }
              catch (Throwable t)
              {
                  log.log(Level.FINE, "Error loading class (could be normal)", t);
                  unifiedELAvailable = false;
              }
  
              //log.info("MyFaces Unified EL support " + (unifiedELAvailable ? "enabled" : "disabled"));
          }
          return unifiedELAvailable;
      }
docs: This method determines if Unified EL is present.
  
  Eager initialization is used for performance. This means Unified EL binaries
  should not be added at runtime after this variable has been set.
  @return true if UEL is available, false otherwise.