specific point in time, rather than a document that may change over time.
  
  See here for guidance on getting permanent links to files: https://help.github.com/en/articles/getting-permanent-links-to-files
  
  Please use the following format for linking documentation:
  - [KEP]: <link>
  - [Usage]: <link>
  - [Other doc]: <link>

/**
 * A {@link List} whose contents will never change, with many other important properties detailed at
 * {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @see ImmutableMap
 * @see ImmutableSet
 * @author Kevin Bourrillion
 * @since 2.0
 */

 *   <li>A {@code Range} is serializable if it has no bounds, or if each bound is serializable.
 * </ul>
 *
 * <h3>Further reading</h3>
 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/RangesExplained">{@code Range}</a>.
 *
 * @author Kevin Bourrillion
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible

  specific point in time, rather than a document that may change over time.
  
  See here for guidance on getting permanent links to files: https://help.github.com/en/articles/getting-permanent-links-to-files
  
  Please use the following format for linking documentation:
  - [KEP]: <link>
  - [Usage]: <link>
  - [Other doc]: <link>

 * {@link com.google.common.util.concurrent.AtomicLongMap} instead. Note, however, that unlike
 * {@code Multiset}, {@code AtomicLongMap} does not automatically remove zeros.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multiset">{@code Multiset}</a>.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

     Rights.

  d. Effective Technological Measures means those measures that, in the
     absence of proper authority, may not be circumvented under laws
     fulfilling obligations under Article 11 of the WIPO Copyright
     Treaty adopted on December 20, 1996, and/or similar international
     agreements.

  e. Exceptions and Limitations means fair use, fair dealing, and/or

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

 * {@code HashBiMap} and its inverse are both serializable.
 *
 * <p>This implementation guarantees insertion-based iteration order of its keys.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap} </a>.
 *
 * @author Louis Wasserman
 * @author Mike Bostock
 * @since 2.0
 */
@GwtCompatible

 * implementations, synchronization is unnecessary between a thread that writes to one cell and a
 * thread that reads from another.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#table">{@code Table}</a>.
 *
 * @author Jared Levy
 * @since 10.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Provides static utility methods for creating and working with {@link Multiset} instances.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionUtilitiesExplained#multisets">{@code
 * Multisets}</a>.
 *
 * @author Kevin Bourrillion
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0