Fix link to Spring Framework javadoc

build.gradle

@@ -37,7 +37,7 @@ ext {
 	springVersion = '4.2.5.RELEASE'
 	javadocLinks = [
 		'http://docs.oracle.com/javase/8/docs/api/',
-		'http://docs.spring.io/spring-framework/docs/$springVersion/javadoc-api/',
+		"http://docs.spring.io/spring-framework/docs/$springVersion/javadoc-api/",
 		'https://docs.jboss.org/hibernate/stable/beanvalidation/api/',
 		'https://docs.jboss.org/hibernate/stable/validator/api/'
 	] as String[]