import static com.google.common.collect.testing.features.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.ListFeature.SUPPORTS_REMOVE_WITH_INDEX;

/// tip

The next sections are **not necessarily "advanced"**.

And it's possible that for your use case, the solution is in one of them.

///

## Read the Tutorial first { #read-the-tutorial-first }

The next sections assume you already read the main [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

And it can also be used by yourself, to debug, check and test the same application.

## The `password` flow { #the-password-flow }

Now let's go back a bit and understand what is all that.

The `password` "flow" is one of the ways ("flows") defined in OAuth2, to handle security and authentication.

OAuth2 was designed so that the backend or API could be independent of the server that authenticates the user.

   * default rounding mode: if the two nearest representable values are equally near, the one with
   * the least significant bit zero is chosen. (In such cases, both of the nearest representable
   * values are even integers; this method returns the one that is a multiple of a greater power of
   * two.)
   *

  public void testFilteredValuesClear() {
    Map<String, Integer> unfiltered = createUnfiltered();
    unfiltered.put("one", 1);
    unfiltered.put("two", 2);
    unfiltered.put("three", 3);
    unfiltered.put("four", 4);
    Map<String, Integer> filtered = Maps.filterValues(unfiltered, EVEN);
    assertEquals(ImmutableMap.of("one", 1, "two", 2, "three", 3, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("two", 2, "four", 4), filtered);

		logger.Info("bucketMetacache.findCache: bucket %s does not match this bucket %s", o.Bucket, b.bucket)
		debug.PrintStack()
		return metacache{}
	}

	// Grab a write lock, since we create one if we cannot find one.
	b.mu.Lock()
	defer b.mu.Unlock()

	// Check if exists already.
	if c, ok := b.caches[o.ID]; ok {
		c.lastHandout = time.Now()
		b.caches[o.ID] = c
		b.debugf("returning existing %v", o.ID)

	}

	if err = checkPathLength(dirPath); err != nil {
		return err
	}

	if err = reliableRemoveAll(dirPath); err != nil {
		switch {
		case isSysErrNotDir(err):
			// File path cannot be verified since one of
			// the parents is a file.
			return errFileAccessDenied
		case isSysErrPathNotFound(err):
			// This is a special case should be handled only for
			// windows, because windows API does not return "not a

  }

  /**
   * Tries to perform a "full" garbage collection cycle (including processing of weak references and
   * invocation of finalize methods) and waits for it to complete. Ensures that at least one weak
   * reference has been cleared and one {@code finalize} method has been run before this method
   * returns. This method may be useful when testing the garbage collection mechanism itself, or

 *   <dt>{@link Multiset}
 *   <dd>An extension of {@link java.util.Collection} that may contain duplicate values like a
 *       {@link java.util.List}, yet has order-independent equality like a {@link java.util.Set}.
 *       One typical use for a multiset is to represent a histogram.
 *   <dt>{@link ClassToInstanceMap}
 *   <dd>An extension of {@link java.util.Map} that associates a raw type with an instance of that
 *       type.
 * </dl>
 *

 *   <dt>{@link Multiset}
 *   <dd>An extension of {@link java.util.Collection} that may contain duplicate values like a
 *       {@link java.util.List}, yet has order-independent equality like a {@link java.util.Set}.
 *       One typical use for a multiset is to represent a histogram.
 *   <dt>{@link ClassToInstanceMap}
 *   <dd>An extension of {@link java.util.Map} that associates a raw type with an instance of that
 *       type.
 * </dl>
 *