diff --git a/accurest-core/src/main/groovy/io/coderate/accurest/util/StubMappingConverter.groovy b/accurest-core/src/main/groovy/io/coderate/accurest/util/StubMappingConverter.groovy
index ee2528c7c6..439224eccd 100644
--- a/accurest-core/src/main/groovy/io/coderate/accurest/util/StubMappingConverter.groovy
+++ b/accurest-core/src/main/groovy/io/coderate/accurest/util/StubMappingConverter.groovy
@@ -28,9 +28,9 @@ class StubMappingConverter {
 	}
 
 	static def transformValue(def value, Closure closure) {
-		if (value instanceof String) {
+		if (value instanceof String && value) {
 			try {
-				def json = new JsonSlurper().parseText(value as String)
+				def json = new JsonSlurper().parseText(value)
 				if (json instanceof Map) {
 					return convertPlaceholders(json, closure)
 				}