How to access the same instance of the control database class from different threads?

Question

JDBC

The bottom line is, I have a class (DBmanager) that works with the database (Adds, deletes, changes rows, checks for their presence, etc.). There is a second class, which is a server (ServerChat),
which, with each new connected user, creates a new thread to work with it. But here we have one DBmanager object, and it is created when the ServerChat class is created. Those. at any time, a call from different threads to an object of the DBmanager class can turn out ... How can I get around this, or am I misunderstanding something?

public class ServerChat {

    private DBManager dbManager;

    public ServerChat() {
        dbManager = new DBManager();
    }



 public void start(int port) {

        try (ServerSocket connectionListener = new ServerSocket(port)) {
            while (true) {
                Здесь слушается подключение и создается новый поток на каждого подключенного.
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In the main method, an instance of the ServerChat class is created and the start method is called.