This article is a legacy article. It applies to previous versions of the Liferay product. While the article is no longer maintained, the information may still be applicable.
Reject processAction for http://localhost:8080/home on portletname_WAR_portlename6_0portlet_INSTANCE_D1J0NullPointerException stacktrace.Resolution
This issue is intended behavior: the error message appears due to the extra security check which has been introduced by LPS-27674 which does not allow the portlet to call processAction(...) or serverResource(...) from anywhere.
- Add the following tag into 
liferay-portlet.xml(located inside any project'sdocroot/WEB-INF):<liferay-portlet-app> <portlet> <add-default-resource>true</add-default-resource> </portlet> </liferay-portlet-app>
 - Either set 
portlet.add.default.resource.check.enabled=falseor include your custom portlet inportlet.add.default.resource.check.whitelist.