# OpenAPI Webhooks { #openapi-webhooks }

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

                    public Source(String[] some) {}
                    public String foo(String[] bar) { return "some"; }
                }
            """,
            v2 = """
                import $nullableAnnotationName;
                public class Source {
                    public Source(@Nullable String[] some) {}
                    public String foo(@Nullable String[] bar) { return "some"; }
                }
            """

#### The time to answer helps the attackers { #the-time-to-answer-helps-the-attackers }

At that point, by noticing that the server took some microseconds longer to send the "Incorrect username or password" response, the attackers will know that they got _something_ right, some of the initial letters were right.

        new File("/home/build/x/y/z.jar").toURI(),
        ClassPath.getClassPathEntry(new File("/home/build/outer.jar"), "x/y/z.jar").toURI());
    assertEquals(
        "/home/build/x y.jar",
        ClassPath.getClassPathEntry(new File("/home/build/outer.jar"), "x y.jar").getFile());
  }

  public void testGetClassPathFromManifest_nullManifest() {
    assertThat(ClassPath.getClassPathFromManifest(new File("some.jar"), null)).isEmpty();
  }

                    public Source(@Nullable String some) {}
                    @Nullable public String nonFinalField = null;
                    public String foo(@Nullable String bar) { return "some"; }
                }
            """,
            v2 = """
                public class Source {
                    public Source(String some) {}
                    public String nonFinalField = "some";

    with pytest.raises(WebSocketDisconnect):
        with client.websocket_connect("/items/bar/ws?token=some-token") as websocket:
            message = "Message one"
            websocket.send_text(message)
            data = websocket.receive_text()
            assert data == "Session cookie or query token value is: some-token"
            data = websocket.receive_text()

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  short readShort();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  int readUnsignedShort();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  char readChar();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  int readInt();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  long readLong();

Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.

So, during that time, the computer can go and do some other work, while "slow-file" 📝 finishes.

      </searchConfiguration>

                fun Int.invoke(some: Int) {}
                operator fun Boolean.invoke(some: Int) {}

                fun String.invoke(some: Int) {}
                operator fun Long.invoke(some: Int) {}

                fun Float.invoke(some: Int) {}
                infix fun Byte.invoke(some: Int) {}

                interface Source {
                    infix fun String.plus(some: List<Int>): String