I'm trying to enumerate all the permissions used by all the installed packages, however when I check the requestedPermissions property for each of my installed packages it is always null. The following is the code that does this:

private HashMap<String, List<String>> buildMasterList() {
    HashMap<String, List<String>> result = new HashMap<String, List<String>>();

    List<PackageInfo> packages = getPackageManager().getInstalledPackages(PackageManager.GET_PERMISSIONS);

    for (int i = 0; i < packages.size(); i++) {
        String[] packagePermissions = packages.get(i).requestedPermissions;
        Log.d("AppList", packages.get(i).packageName);
        if (packagePermissions != null) {
            for (int j = 0; j < packagePermissions.length; j++) {
                if (!result.containsKey(packagePermissions[j])) {
                    result.put(packagePermissions[j], new ArrayList<String>());
                }
                result.get(packagePermissions[j]).add(packages.get(i).packageName);
            }
        }
        else {
            Log.d("AppList", packages.get(i).packageName + ": no permissions");
        }
    }

    return result;
}

Edit: Oops! I just needed to pass the PackageManager.GET_PERMISSIONS flag to getInstalledPackages(). Updated the code snippet.