```

////

/// tip

We are using an invented header to simplify this example.

But in real cases you will get better results using the integrated [Security utilities](security/index.md){.internal-link target=_blank}.

///

## Another module with `APIRouter`

 *   <li>Running tasks <i>cannot</i> be interrupted. (Note that {@code newSequentialExecutor} does
 *       not return {@code Future} objects, so it doesn't support interruption directly, either.
 *       However, utilities that <i>use</i> that executor have the ability to interrupt tasks
 *       running on it. This class, by contrast, does not expose an {@code Executor} API.)
 * </ul>
 *

## Install `passlib`

PassLib is a great Python package to handle password hashes.

It supports many secure hashing algorithms and utilities to work with them.

The recommended algorithm is "Bcrypt".

Make sure you create a [virtual environment](../../virtual-environments.md){.internal-link target=_blank}, activate it, and then install PassLib with Bcrypt:

 * and {@link UnsignedBytes}.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
// TODO(kevinb): how to prevent warning on UnsignedBytes when building GWT
// javadoc?
@GwtCompatible
@ElementTypesAreNonnullByDefault

import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Utilities for treating interruptible operations as uninterruptible. In all cases, if a thread is
 * interrupted during such a call, the call continues to block until the result is available or the

import java.nio.charset.StandardCharsets;

/**
 * Static methods pertaining to ASCII characters (those in the range of values {@code 0x00} through
 * {@code 0x7F}), and to strings containing such characters.
 *
 * <p>ASCII utilities also exist in other classes of this package:
 *
 * <ul>
 *   <!-- TODO(kevinb): how can we make this not produce a warning when building gwt javadoc? -->

 * reasonable and it will be fine.
 *
 * <ul>
 *   <li>If checking whether the <i>caller</i> has violated your method or constructor's contract
 *       (such as by passing an invalid argument), use the utilities of the {@link Preconditions}
 *       class instead.
 *   <li>If checking an <i>impossible</i> condition (which <i>cannot</i> happen unless your own

 * neither Unicode-aware nor locale-dependent.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Chars {
  private Chars() {}

  /**

 * either {@link Short} or {@link Arrays}.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Shorts extends ShortsMethodsForWeb {
  private Shorts() {}

  /**

 * either {@link Short} or {@link Arrays}.
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Shorts extends ShortsMethodsForWeb {
  private Shorts() {}

  /**