* There can be **multiple processes** of the **same program** running at the same time.

If you check out the "task manager" or "system monitor" (or similar tools) in your operating system, you will be able to see many of those processes running.

import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Specifies the priority of a bean implementation when multiple implementations
 * of the same type are available.
 * <p>
 * Higher values indicate higher priority. When multiple implementations of the same
 * type exist, the one with the highest priority will be selected for injection.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Priority(100)

  }

  @Test
  fun testNoUncompress() {
    val response = response("https://httpbin.org/brotli", "XXXX".encodeUtf8())

    val same = brotliInterceptor.decompress(response)

    val responseString = same.body.string()
    assertThat(responseString).isEqualTo("XXXX")
  }

  @Test
  fun testFailsUncompress() {
    val response =

    }
  }

  /**
   * Returns a hash code, having the same bit length as each of the input hash codes, that combines
   * the information of these hash codes in an ordered fashion. That is, whenever two equal hash
   * codes are produced by two calls to this method, it is <i>as likely as possible</i> that each
   * was computed from the <i>same</i> input hash codes in the <i>same</i> order.
   *

    }

    // Test providePrimaryInvertibleCryptographer
    @Test
    public void test_providePrimaryInvertibleCryptographer() {
        // Test that the method returns the same instance
        InvertibleCryptographer first = securityResourceProvider.providePrimaryInvertibleCryptographer();
        InvertibleCryptographer second = securityResourceProvider.providePrimaryInvertibleCryptographer();

        assertNotNull(instance1);
        assertNotNull(instance2);
        // The second setInstance replaces the first, so they should not be the same
        assertNotSame(instance1, instance2);
        // Getting instance again should return the same as instance2
        assertSame(instance2, LogStream.getInstance());
    }

    @Test
    void testLogStreamInheritsFromPrintStream() {

You would have **one single `engine` object** for all your code to connect to the same database.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[14:18] hl[14:15,17:18] *}

Using `check_same_thread=False` allows FastAPI to use the same SQLite database in different threads. This is necessary as **one single request** could use **more than one thread** (for example in dependencies).

///

### Pydantic v1 and v2 on the same app { #pydantic-v1-and-v2-on-the-same-app }

It's **not supported** by Pydantic to have a model of Pydantic v2 with its own fields defined as Pydantic v1 models or vice versa.

```mermaid
graph TB
    subgraph "❌ Not Supported"

But in our code we are actually using `secrets.compare_digest()`.

In short, it will take the same time to compare `stanleyjobsox` to `stanleyjobson` than it takes to compare `johndoe` to `stanleyjobson`. And the same for the password.

That way, using `secrets.compare_digest()` in your application code, it will be safe against this whole range of security attacks.

        // Act & Assert
        // unwrap to interface itself should return same instance
        CredentialsInternal unwrapped = creds.unwrap(CredentialsInternal.class);
        assertNotNull(unwrapped, "unwrap to CredentialsInternal returns instance");
        assertSame(creds, unwrapped, "unwrap returns the same object instance");