public static void rotate(int[] array, int distance, int fromIndex, int toIndex) {
    // There are several well-known algorithms for rotating part of an array (or, equivalently,
    // exchanging two blocks of memory). This classic text by Gries and Mills mentions several:
    // https://ecommons.cornell.edu/bitstream/handle/1813/6292/81-452.pdf.
    // (1) "Reversal", the one we have here.

Here's a little bit of that history.

## Alternatives { #alternatives }

I have been creating APIs with complex requirements for several years (Machine Learning, distributed systems, asynchronous jobs, NoSQL databases, etc), leading several teams of developers.

As part of that, I needed to investigate, test and use many alternatives.

The history of **FastAPI** is in great part the history of its predecessors.

    assertEquals(a, navigableMap.pollLastEntry());
    assertTrue(navigableMap.isEmpty());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a, navigableMap.firstEntry());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(SEVERAL)
  public void testPollFirst() {
    assertEquals(a, navigableMap.pollFirstEntry());

    assertEquals(a, navigableMap.pollLastEntry());
    assertTrue(navigableMap.isEmpty());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a, navigableMap.firstEntry());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(SEVERAL)
  public void testPollFirst() {
    assertEquals(a, navigableMap.pollFirstEntry());

                    return union(emptySet(), newHashSet(elements));
                  }
                })
            .named("empty U set")
            .withFeatures(
                CollectionSize.ONE, CollectionSize.SEVERAL, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {
                  @Override

  public void testSingletonMapLast() {
    assertEquals(a.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a.getKey(), navigableMap.firstKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testLast() {
    assertEquals(c.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(absent = ZERO)

      assertOneToOne();
    } catch (UnsupportedOperationException tolerated) {
    }
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSetCount_threeToThree_addSupported() {
    assertThreeToThree();
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testSetCount_threeToThree_removeSupported() {
    assertThreeToThree();

  public void testSingletonMapLast() {
    assertEquals(a.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a.getKey(), navigableMap.firstKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testLast() {
    assertEquals(c.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(absent = ZERO)

## OAuth2 { #oauth2 }

OAuth2 is a specification that defines several ways to handle authentication and authorization.

It is quite an extensive specification and covers several complex use cases.

It includes ways to authenticate using a "third party".

      assertOneToOne();
    } catch (UnsupportedOperationException tolerated) {
    }
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSetCount_threeToThree_addSupported() {
    assertThreeToThree();
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testSetCount_threeToThree_removeSupported() {
    assertThreeToThree();