Firebase Admin Sdk for Java not working. I can't get any result or data

Question

I have a firebase admin sdk project in java. I have a problem, I cannot get any data or result from my firebase server. here is my project: [[enter image description here](https://i.sstatic.net/Gn8XU.png)](https://i.sstatic.net/V9ZyJ.png)

I tried at python and program working as normal. My Firebase Database Rules are public.

Answer 1

Problem solved. I gave the listener some time to get the data. here is the code:

        ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot snapshot) {
            System.out.println(snapshot);
        }

        @Override
        public void onCancelled(DatabaseError error) {

        }
    });
    TimeUnit.MINUTES.sleep(1);