Exporting Database

public void ExportNote(View view) {

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

                if (sd.canWrite()) {
                    SQLiteDatabase db = dbHelper.getReadableDatabase();
                    String currentDBPath =db.getPath();
                    String backupDBPath  = "/BackupFolder/DatabaseName";
                    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();
                    Toast.makeText(getBaseContext(), backupDB.toString(), Toast.LENGTH_LONG).show();

               }
           } catch (Exception e) {

                Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG).show();

            }
        }

    }

// when i call this function i get Filenotfoundexception /data/data/data/com.example.jawad.myapp/database/imagedb open failed ? why