Rename the file com.liferay.dynamic.data.mapping.data.provider.instance-4.0.19-javadoc.jar to com.liferay.dynamic.data.mapping.data.provider.instance-4.0.19-javadoc.zip
Use your favourite unzip tool (WinRAR / WinZIP) to extract it, now you have a folder com.liferay.dynamic.data.mapping.data.provider.instance-4.0.19-javadoc
Double click index.html will open the index page on your default web browser.
