getInstalledApplications returning null

getInstalledApplications returning null

I am trying to retrieve a list of apps that are installed on the
phone/emulator. I am using the following snippet to return the list of
apps, however, it is returning null. Do I have to add some permission in
Android Manifest or am I missing something else?
pManager.getInstalledApplications(PackageManager.GET_META_DATA);