Request multiple permissions android java

check_perms.java

String[] perms = {
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
};

public void check_perms(){
    for (String perm: perms) {
        if (ContextCompat.checkSelfPermission(this, perm) != PackageManager.PERMISSION_GRANTED) {
            // request permission
            if (ActivityCompat.shouldShowRequestPermissionRationale(this, perm)){
                new AlertDialog.Builder(this)
                        .setTitle("Permission Needed")
                        .setMessage("This app needs a certain permission to work properly")
                        .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                ActivityCompat.requestPermissions(Base.this, perms, 1);
                            }
                        })
                        .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialogInterface, int i) {
                                dialogInterface.dismiss();
                            }
                        })
                        .create()
                        .show();
                return;
            } else {
                ActivityCompat.requestPermissions(this, perms, 1);
            }
        }
    }
}