> For the complete documentation index, see [llms.txt](https://divine.qibergames.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://divine.qibergames.com/advanced-usage/images-and-media.md).

# Service implementations

In case, you want to use a single implementation of your service interface, throughout your entire application, you can use the following code.

```java
@Service(implementation = RedisSessionManager.class)
interface SessionManager {
    Session createSession();
}

@Service
class RedisSessionManager implements SessionManager {
    @Override
    public Session createSession() {
        return createMySession();
    }
}

void handleAuthentication(User user) {
    SessionManager sessionManager = Container.get(SessionManager.class);
    
    if (authorized)
        user.setSession(sessionManager.createSession());
}
```

You can also manually implement a service interface, using the following code.

```java
@Service
interface DatabaseConnector {
    void connect();
}

@Service
class MySQLConnector implements DatabaseConnector {
    @Override
    public void connect() {
        requestMySQLConnection();
    }
}

void initDatabase() {
    Container.implement(DatabaseConnector.class, MySQLConnector.class);
}

void useDatabase() {
    DatabaseConnector connector = Container.get(DatabaseConnector.class);
    assert connector instanceof MySQLConnector;
}
```