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Thumbnails section is not working with GroupDocs.viewer for Java 2.1


I am evaluating GroupDocs.viewer for Java with version 2.1. When I try to view the document with the samples provided, thumbnails is keep on loading with below js error.

“Message: Unable to get value of the property ‘0’: object is null or undefined;Line: 1;Char: 142980;Code: 0;URI: http://localhost:9080/GroupDocsWeb/GetJsHandler?script=GroupdocsViewer.all.min.js

Server used:Websphere; Browser used:IE9.

Please help resolving this issue.

Note: I dont have permission for attaching stuffs.


Hello Praveenkanna!

We are sorry to see that you get this error. I assume you are using the Java Spring Framework sample. It can be fixed with changing the getImageUrlsHandler method of the HomeController class. Replace this line
return jsonOut(new Gson().toJson(viewerHandler.getImageUrlsHandler(request, response)));
with this one
return jsonOut(viewerHandler.getImageUrlsHandler(request, response));
or you can download the latest sample available on our github repo:


Thanks Ihor. After making changes mentioned by you, thumbnails images are getting loaded properly. – Regards, Praveenkanna.