ivicac/liferay-portal — comment on commit 144b4fa963a19f805424cc1351d99b8d5ff365f1
File: portal-service/src/com/liferay/portlet/documentlibrary/util/DLPreviewableProcessor.java line 122
By caorongjin:

This method actually is problematic. Use doGetThumbnailAsStream() instead. It does not work when you are not using FileSystemStore:

http://issues.liferay.com/browse/LPS-25822