### Is concurrency better than parallelism? { #is-concurrency-better-than-parallelism }

Nope! That's not the moral of the story.

Concurrency is different than parallelism. And it is better on **specific** scenarios that involve a lot of waiting. Because of that, it generally is a lot better than parallelism for web application development. But not for everything.

    id: what-did-you-do
    attributes:
      label: "What did you do?"
      description: "If possible, provide a recipe for reproducing the error. A complete runnable program is good. A link on [go.dev/play](https://go.dev/play) is better. A failing unit test is the best."
    validations:
      required: true
  - type: textarea
    id: actual-behavior
    attributes:
      label: "What did you see happen?"
    validations:
      required: true

    // unless it's actually going to be used; validate() is called for all set method calls, so it
    // needs to be fast.
    // (We could instead generate the message once, when the set is created, but zero is better.)
    if (!validator.get()) {
      throw new IllegalStateException(errorMessage.get());
    }
  }

I (the author, [@tiangolo](https://x.com/tiangolo)) will review it thoroughly and get back to you.

## Public Discussions

Please restrain from publicly discussing a potential security vulnerability. 🙊

It's better to discuss privately and try to find a solution first, to limit the potential impact as much as possible.

---

Thanks for your help!

{* ../../docs_src/path_params_numeric_validations/tutorial003.py hl[7] *}

### Better with `Annotated` { #better-with-annotated }

Keep in mind that if you use `Annotated`, as you are not using function parameter default values, you won't have this problem, and you probably won't need to use `*`.

# The Gradle tests need the pom.xml only to read its version number.
# (And the file needs to be two directory levels up from the Gradle build file.)
# TODO(cpovirk): Find a better way to give them that information.
cp pom.xml "${GRADLE_TEMP}"

for version in 5.6.4 7.0.2; do
  # Enter a subshell so that we return to the current directory afterward.
  (
    cp -r integration-tests "${GRADLE_TEMP}/${version}"
    cd "${GRADLE_TEMP}/${version}/gradle"

 * of EventBus may be better written using <a
 * href="https://kotlinlang.org/docs/coroutines-guide.html">Kotlin coroutines</a>, including <a
 * href="https://kotlinlang.org/docs/flow.html">Flow</a> and <a
 * href="https://kotlinlang.org/docs/channels.html">Channels</a>. Yet other usages are better served
 * by individual libraries that provide specialized support for particular use cases.
 *

    linkedHashMultiset = LinkedHashMultiset.create(size);
    treeMultiset = TreeMultiset.create();

    Random random = new Random();

    int sizeRemaining = size;

    // TODO(kevinb): generate better test contents for multisets
    while (sizeRemaining > 0) {
      // The JVM will return interned values for small ints.
      Integer value = random.nextInt(1000) + 128;

If you want to secure your API, there are several better things you can do, for example:

* Make sure you have well defined Pydantic models for your request bodies and responses.
* Configure any required permissions and roles using dependencies.

import org.jspecify.annotations.NullUnmarked;

/**
 * Utility class for being able to seed a {@link Random} value with a passed in seed from a
 * benchmark parameter.
 *
 * <p>TODO: Remove this class once Caliper has a better way.
 *
 * @author Nicholaus Shupe
 */
@NullUnmarked
public final class SpecialRandom extends Random {
  public static SpecialRandom valueOf(String s) {