Database not exporting to sd card

I'm almost new to Android development. I'm trying to backup my apps DB to SD card but failed. I tried below the codes but it not work. Event any error I did not get.

File sd = Environment.getExternalStorageDirectory();
File data = Environment.getDataDirectory();     
if (sd.canWrite()) {
   String currentDBPath = "//data//"+ "app.myapp.test" +"//databases//"+"my_database";
   String backupDBPath = "/Backup/database";
   File currentDB = new File(data, currentDBPath);
   File backupDB = new File(sd, backupDBPath);

   FileChannel src = new FileInputStream(currentDB).getChannel();
   FileChannel dst = new FileOutputStream(backupDB).getChannel();
   dst.transferFrom(src, 0, src.size());
   src.close();
   dst.close();
 }

Any information will be appreciated.