*
 * <p>Most methods in this class treat absent values and zero values identically, as individually
 * documented. Exceptions to this are {@link #containsKey}, {@link #size}, {@link #isEmpty}, {@link
 * #asMap}, and {@link #toString}.
 *
 * <p>Instances of this class may be used by multiple threads concurrently. All operations are
 * atomic unless otherwise noted.
 *
 * <p>Instances of this class are serializable if the keys are serializable.

import org.eclipse.aether.util.repository.AuthenticationBuilder;

/**
 * <strong>Warning:</strong> This is an internal utility class that is only public for technical reasons, it is not part
 * of the public API. In particular, this class can be changed or deleted without prior notice.
 *
 */
public class RepositoryUtils {

    private static String nullify(String string) {
        return (string == null || string.isEmpty()) ? null : string;

# `Response` class

You can declare a parameter in a *path operation function* or dependency to be of type `Response` and then you can set data for the response like headers or cookies.

You can also use it directly to create an instance of it and return it from your *path operations*.

You can import it directly from `fastapi`:

```python
from fastapi import Response
```

from typing import List, Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: List[str] = []


@app.post("/items/")
async def create_item(item: Item) -> Item:
    return item


@app.get("/items/")
async def read_items() -> List[Item]:

but that goroutine may create other goroutines,
which run concurrently.
</p>

<p class="rule">
If a package <code>p</code> imports package <code>q</code>, the completion of
<code>q</code>'s <code>init</code> functions happens before the start of any of <code>p</code>'s.
</p>

<p class="rule">
The completion of all <code>init</code> functions is synchronized before

import jakarta.annotation.Resource;

/**
 * @author shinsuke
 * @author Shunji Makino
 */
public class AdminCrawlinginfoAction extends FessAdminAction {

    public static final String ROLE = "admin-crawlinginfo";

    private static final Logger logger = LogManager.getLogger(AdminCrawlinginfoAction.class);

    // ===================================================================================

 * they are available to GWT.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class DerivedGoogleCollectionGenerators {
  public static class MapGenerator<K extends @Nullable Object, V extends @Nullable Object>
      implements TestMapGenerator<K, V>, DerivedGenerator {

 *
 * @author Kevin Bourrillion
 * @since 3.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class Interners {
  private Interners() {}

  /**
   * Builder for {@link Interner} instances.
   *
   * @since 21.0
   */
  public static class InternerBuilder {
    private final MapMaker mapMaker = new MapMaker();
    private boolean strong = true;

    private InternerBuilder() {}

# History, Design and Future

Some time ago, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">a **FastAPI** user asked</a>:

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives

# História, Design e Futuro

Há algum tempo, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">um usuário **FastAPI** perguntou</a>:

> Qual é a história desse projeto? Parece que surgiu do nada e se tornou incrível em poucas semanas [...]

Aqui está um pouco dessa história.

## Alternativas