import com.esotericsoftware.kryo.serializers.CollectionSerializer;
import com.esotericsoftware.kryo.serializers.MapSerializer;

/**
 * A serializer class for handling object serialization and deserialization.
 * <p>
 * This class provides serialization capabilities using different serializers,
 * currently supporting Kryo and JavaBin serialization formats. The serializer

With a response model, FastAPI will use Pydantic to serialize the data to JSON, without using intermediate steps, like converting it with `jsonable_encoder`, which would happen in any other case.

And under the hood, Pydantic uses the same underlying Rust mechanisms as `orjson` to serialize to JSON, so you will already get the best performance with a response model.

    }

    /**
     * Serialize the inbound Model instance to a StringWriter, perform the regex replacement to resolve
     * POM expressions, then re-parse into the resolved Model instance.
     * <p>
     * <b>NOTE:</b> This will result in a different instance of Model being returned!!!
     *
     * @param model The inbound Model instance, to serialize and reference for expression resolution

@app.post("/items/")
async def create_item(item: Item, project_id: Annotated[int, Query(...)]): ...
```

## Return Type or Response Model

When possible, include a return type. It will be used to validate, filter, document, and serialize the response.

```python
from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None

        start = System.currentTimeMillis();
        SerializeUtil.serialize(hmap);
        System.out.println("HashMap serialize:" + (System.currentTimeMillis() - start));

        start = System.currentTimeMillis();
        SerializeUtil.serialize(amap);
        System.out.println("ArrayMap serialize:" + (System.currentTimeMillis() - start));
    }

    private static class MyKey {

        } catch (final JsonProcessingException e) {
            logger.warn("[RAG] Failed to serialize SSE data. event={}", event, e);
        }
    }

    /**
     * Writes a JSON response to the HTTP response.
     *
     * @param response the HTTP response
     * @param status the HTTP status code
     * @param data the data to serialize as JSON
     * @throws IOException if an I/O error occurs
     */

```

</div>

Then go to the `/docs` UI, you will see that **FastAPI** is using these **models** to **document** the API, and it will use them to **serialize** and **validate** the data too.

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

	log.SetPrefix("go_android_exec: ")
	exitCode, err := runMain()
	if err != nil {
		log.Fatal(err)
	}
	os.Exit(exitCode)
}

func runMain() (int, error) {
	// Concurrent use of adb is flaky, so serialize adb commands.
	// See https://github.com/golang/go/issues/23795 or
	// https://issuetracker.google.com/issues/73230216.
	lockPath := filepath.Join(os.TempDir(), "go_android_exec-adb-lock")

        SsoLoginException originalException = new SsoLoginException(message, cause);

        // Serialize the exception
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        oos.writeObject(originalException);
        oos.close();

        // Deserialize the exception
        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());

                }
            }
        });
    }

    /**
     * Serializes request parameters to a compressed and encoded string.
     *
     * @param parameters Array of request parameters to serialize
     * @return Base64-encoded, GZIP-compressed JSON string of parameters
     * @throws SearchQueryException if serialization fails
     */