//Creating and initializing User class object User user = new User("user1234", "abc", "xyz", "First", "January", "2001"); //Getting Instance of Firebase realtime database FirebaseDatabase databaseInstance = FirebaseDatabase.getInstance(); //Getting Reference to a User node, (it will be created if not already there) DatabaseReference userNode = database.getReference("User"); //Writing the User class object to that reference userNode.setValue(user);