Remove node from Firebase DB

RemoveNode.java

DatabaseReference testRef = mRef.child("test");

        testRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot db : dataSnapshot.getChildren()){
                    db.child("isAvailable").getRef().setValue(null);
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });