replace isBlank with java8 compatible method

Helpers.jrag

@@ -59,7 +59,7 @@ aspect Helpers {
     if (value == null || value.equals("null")) {
       return StringElement.of("null");
     }
-    if (value.isBlank()) {
+    if (value.trim().isEmpty()) {
       return StringElement.of(value);
     }
     // simple test, check for special characters