The client (browser) will know that the response comes from the correct server because it is using the cryptography they agreed using the **HTTPS certificate** before.

### Multiple Applications { #multiple-applications }

In the same server (or servers), there could be **multiple applications**, for example, other API programs or a database.

	<fieldset class="mb-3">
		<legend><la:message key="labels.index_lang" /></legend>
		<label for="langSearchOption"><la:message key="labels.index_lang" /></label>
		<la:select property="lang" styleId="langSearchOption" multiple="true"
			styleClass="form-control">
			<c:forEach var="item" items="${langItems}">
				<la:option value="${f:u(item.value)}">${f:h(item.label)}</la:option>
			</c:forEach>
		</la:select>
	</fieldset>

	<fieldset class="mb-3">
		<legend><la:message key="labels.index_lang" /></legend>
		<label for="langSearchOption"><la:message key="labels.index_lang" /></label>
		<la:select property="lang" styleId="langSearchOption" multiple="true"
			styleClass="form-control">
			<c:forEach var="item" items="${langItems}">
				<la:option value="${f:u(item.value)}">${f:h(item.label)}</la:option>
			</c:forEach>
		</la:select>
	</fieldset>

        new SecureRandom().nextBytes(secondFileId);

        // When - set file ID multiple times
        assertDoesNotThrow(() -> {
            request.setFileId(firstFileId);
            request.setFileId(secondFileId);
            request.setFileId(testFileId);
        }, "Should handle multiple setFileId calls");
    }

    @Test
    @DisplayName("Should test interface with anonymous implementation")

  }

  /**
   * Returns the number of times {@link Cache} lookup methods have returned an uncached (newly
   * loaded) value, or null. Multiple concurrent calls to {@link Cache} lookup methods on an absent
   * value can result in multiple misses, all returning the results of a single cache load
   * operation.
   */
  public long missCount() {
    return missCount;
  }

  /**

## Dependencies for groups of *path operations* { #dependencies-for-groups-of-path-operations }

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

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

Now let's **refactor** this app a bit to increase **security** and **versatility**.

They tend to require more complex configurations, a message/job queue manager, like RabbitMQ or Redis, but they allow you to run background tasks in multiple processes, and especially, in multiple servers.

But if you need to access variables and objects from the same **FastAPI** app, or you need to perform small background tasks (like sending an email notification), you can simply just use `BackgroundTasks`.

        assertEquals("NTLM", request.getAuthType());
        verify(mockPrincipal, times(1)).getName();
    }

    @ParameterizedTest
    @ValueSource(strings = { "", "   ", "unknown" })
    @DisplayName("supports multiple principal name variants")
    void testPrincipalNameVariants(String name, @Mock HttpServletRequest mockRequest, @Mock Principal mockPrincipal) {
        when(mockPrincipal.getName()).thenReturn(name);

            assertEquals(0, init.getContextFlags());
        }

        @Test
        @DisplayName("Multiple flags can be combined correctly")
        void testMultipleFlagsCombination() {
            NegTokenInit init = new NegTokenInit();

            // Set multiple flags
            init.setContextFlag(NegTokenInit.DELEGATION, true);
            init.setContextFlag(NegTokenInit.INTEGRITY, true);