What techniques exist to improve query performance in Django ORM?

In Spring, the scope of a bean determines the lifecycle and visibility of the bean instance within the container. Main scopes:

• singleton (default) — one instance for the entire Spring container.
• prototype — a new instance is created each time it is requested.
• request — one instance per HTTP request (for web applications).
• session — one instance per HTTP session.
• application — one instance per ServletContext.
• websocket — one instance per WebSocket session.

The application scope differs in that the bean lives throughout the entire web application and is accessible to all sessions and requests, i.e., a scope at the level of ServletContext. Unlike request or session scopes, where a bean is recreated for each request or session, the application scope guarantees a single instance for the entire application runtime in the servlet container.

Example of declaring a bean with application scope:

@Component
@Scope(value = WebApplicationContext.SCOPE_APPLICATION, proxyMode = ScopedProxyMode.TARGET_CLASS)
public class MyAppBean {
    // ...
}

Thus, the application scope is useful for storing data or services that should be shared across the entire web application.