Permission on android studio

private void checkPerms() {

    String[] perms = new String[]{
            Manifest.permission.READ_PHONE_STATE,
            Manifest.permission.RECORD_AUDIO,
            Manifest.permission.READ_CONTACTS,
            Manifest.permission.PROCESS_OUTGOING_CALLS    };

    List<String> requestingPerms = new ArrayList<>();

    for (String perm : perms) {
        if (checkSelfPermission(perm) !=
                PackageManager.PERMISSION_GRANTED) {
            requestingPerms.add(perm);
        }
    }

    if (requestingPerms.size() > 0) {
        requestPermissions(requestingPerms.toArray(new String[requestingPerms.size()]), 0);
    }

}

check permission:

PackageManager pm = getPackageManager();
int hasPerm = pm.checkPermission(Manifest.permission.CAMERA, getPackageName());
if (hasPerm == PackageManager.PERMISSION_GRANTED) {

    selectFile();


}else{

checkPerms()


}