Ggtcf

I'm trying to retrieve an image from firebase realtime database, but my app keeps crashing when opening it.

Database Structure:

[https://i.stack.imgur.com/iWOEK.png][1]

Following is my java code:

public class main2 extends AppCompatActivity 
 TextView txt, url;
 Button btn;
 ImageView img;
 private FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();
 private DatabaseReference reference = firebaseDatabase.getReference();
 private DatabaseReference childreference = reference.child("url");

 @Override
 public void onCreate(Bundle savedInstanceState) 
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main2);

 url = findViewById(R.id.text);
 img = findViewById(R.id.image);

 txt = (TextView) findViewById(R.id.mytext);
 btn = (Button) findViewById(R.id.mybutton);

 btn.setOnClickListener(new View.OnClickListener() 
 @Override
 public void onClick(View v) 
 btn.setVisibility(View.GONE);
 txt.setText("JOINED, Details will be send by notification.");


 

 );


 

 @Override
 protected void onStart() 
 super.onStart();
 childreference.addValueEventListener(new ValueEventListener() 
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) 
 String message = dataSnapshot.getValue(String.class);
 url.setText(message);
 Picasso.get()
 .load(message)
 .into(img);
 

 @Override
 public void onCancelled(@NonNull DatabaseError databaseError) 

 
 );
 

Logcat :

I/Process: Sending signal. PID: 8763 SIG: 9

Make sure you have given read and write permission to your DataBase rules

"rules":
".read": true,
".write": true

For more information refer this