liferay 6.2 addDLFolder fail - web-services

Question

I tried to build a webservice for external system to upload documents.
Each user create a unique folder to store the documents himself uploaded.
In order to that,I was thinking to create different folder with unique name.
I looked up API and find a DLFolderLocalServiceUtil.addFolder(parameter list is way too long to type) method.
The param serviceContext is required and I can't seem to find a way to retrieve it.
So, I put NULL instead. After I build and deploy, I call the method which contains addFolder() from client, NullPointerException occurs on server and an axis exception occurs on client.
faultCode:
{http://schemas.xmlsoap.org/soap/envelope/}Server.userException, faultString: java.rmi.RemoteException.
Is it because I put NULL as a parameter instead of an instance of serviceContext?
If so,how can I get the instance of serviceContext? If I can not, where else could be the problem?
Here's my paramlist:
DLFolderLocalServiceUtil.addFolder(user.getUserId(), user.getGroupId(), user.getGroupId(), true, 10157, "test", "description", false, null);

Answer 1

You could also give DLAppLocalServiceUtil.addFolder a try.
Similarly, the Service Context is a parameter, but I'm able to create a folder with the following
final Folder folder = DLAppLocalServiceUtil.addFolder(
getThemeDisplay().getUserId(),
getThemeDisplay().getScopeGroupId(),
DLFolderConstants.DEFAULT_PARENT_FOLDER_ID,
"Folder Name",
"Folder Description",
new ServiceContext());
In my particular use case, I use the ThemeDisplay from the request object to organize my Document Media elements:
(ThemeDisplay)request.getAttribute(WebKeys.THEME_DISPLAY)
Note: Also in my particular usage, the user that triggers the folder creation will have elevated permissions, as such permissioning may be an issue for non-admin users.