Android migrate(backing up and Rolling Back)

public static void backUpCurrentDB(File db_file, String database_name) {

//call it on onUpgrade
        try {
            String rootPath = Environment.getExternalStorageDirectory()
                    .getAbsolutePath() + "/your_directory/";
            File dir = new File(rootPath);
            if (!dir.exists()) {
                dir.mkdir();
            }

            File sd = Environment.getExternalStorageDirectory();
            File data = Environment.getDataDirectory();

            if (sd.canWrite()) {

                Log.d(TAG, "db file " + db_file.exists() + " exits");

                String currentDBPath = "//data//" + getPackageName() + "//databases//" + database_name + "";

                String backupDBPath = "backup_db_name.db";
                File currentDB = db_file.exists() ? db_file : new File(data, currentDBPath);
                File backupDB = new File(rootPath, backupDBPath);

                if (!backupDB.exists()) {
                    backupDB.createNewFile();
                }

                if (currentDB.exists()) {
                    FileChannel src = new FileInputStream(currentDB).getChannel();
                    FileChannel dst = new FileOutputStream(backupDB).getChannel();
                    dst.transferFrom(src, 0, src.size());
                    src.close();
                    dst.close();
                } else {
                    Log.d("TAG", "current db not exits");
                }
            }
        } catch (Exception e) {
            Log.d("TAG", "backUpCurrentDB");
            e.printStackTrace();
        }
    }

    public static void rollBackCurrentDB(File db_file, String database_name) {
//call it on onDowngrade

        try {
            String rootPath = Environment.getExternalStorageDirectory()
                    .getAbsolutePath() + "/your_directory/";
            File dir = new File(rootPath);
            if (!dir.exists()) {

                return;
            }

            File sd = Environment.getExternalStorageDirectory();
            File data = Environment.getDataDirectory();

            if (sd.canWrite()) {

                Log.d(TAG, " rollback db file " + db_file.exists() + " exits");

                String currentDBPath = "//data//" + getPackageName() + "//databases//" + database_name + "";

                String backupDBPath = "backup_db_name.db";
                File currentDB = db_file.exists() ? db_file : new File(data, currentDBPath);
                File backupDB = new File(rootPath, backupDBPath);

                if (!backupDB.exists()) {
                    return;
                }

                if (currentDB.exists()) {
                    FileChannel src = new FileInputStream(backupDB).getChannel();
                    FileChannel dst = new FileOutputStream(currentDB).getChannel();
                    dst.transferFrom(src, 0, src.size());
                    src.close();
                    dst.close();
                } else {
                    Log.d("TAG", "rollback db not exits");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }