liferay.js can't recognize int return values from JSONWebService

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.0 CE RC2
• Fix Version/s: 6.2.0 CE RC2, 6.2.0 CE RC5
• Component/s: Frontend Infrastructure, Portal Services, Portal Services > Legacy
• Labels: None
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/14139

When JSONWS remote service returns an int value, it is not recognized by liferay.js and the error "The server returned an empty response" is shown.

Test steps:

+ login
+ go to API page
+ choose /assetcategory/get-vocabulary-categories-count
+ enter groupId and vocabularyId
+ click on Invoke

The result is: "The server returned an empty response" instead of 0. The server returns 0 correctly, so its on JS side. See attached screenshot.