code: static boolean isExpression(String expression) {
  
          if (null == expression) {
              return false;
          }
  
          //check to see if attribute has an expression
          int start = expression.indexOf("#{");
          return start != -1 && expression.indexOf('}', start+2) != -1;
      }
docs: /*
  Determine whether String is a value binding expression or not.