private StorageReference mStorageRef;
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mStorageRef = FirebaseStorage.getInstance().getReference().child("20JAN2017.txt");
    System.out.println("......"+mStorageRef);
    Uri url;

    mStorageRef.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {
        @Override
        public void onSuccess(Uri uri)
        {
            FileDownloadTask file = mStorageRef.getFile(uri);

            file.addOnSuccessListener(new OnSuccessListener<FileDownloadTask.TaskSnapshot>() {
                @Override
                public void onSuccess(FileDownloadTask.TaskSnapshot taskSnapshot) {
                    System.out.println("task snapshot..."+taskSnapshot.getStorage());
                }
            });
            file.addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    System.out.println("Error:"+e);

                }
            });
            file.addOnCompleteListener(new OnCompleteListener<FileDownloadTask.TaskSnapshot>() {
                @Override
                public void onComplete(@NonNull Task<FileDownloadTask.TaskSnapshot> task) {
                    System.out.println("task completed");
                }
            });
        }
    });


}