guava README

The project's README from github.com/google/guava. As one markdown file: README.md.

Guava: Google Core Libraries for Java

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Guava is a set of core Java libraries from Google that includes new collection types (such as multimap and multiset), immutable collections, a graph library, and utilities for concurrency, I/O, hashing, primitives, strings, and more! It is widely used on most Java projects within Google, and widely used by many other companies as well.

Guava comes in two flavors:

Adding Guava to your build

Guava's Maven group ID is com.google.guava, and its artifact ID is guava. Guava provides two different "flavors": one for use on a (Java 8+) JRE and one for use on Android or by any library that wants to be compatible with Android. These flavors are specified in the Maven version field as either 33.7.1-jre or 33.7.1-android. For more about depending on Guava, see using Guava in your build.

To add a dependency on Guava using Maven, use the following:

<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>33.7.1-jre</version>
  <!-- or, for Android: -->
  <version>33.7.1-android</version>
</dependency>

To add a dependency using Gradle:

dependencies {
  // Pick one:

  // 1. Use Guava in your implementation only:
  implementation("com.google.guava:guava:33.7.1-jre")

  // 2. Use Guava types in your public API:
  api("com.google.guava:guava:33.7.1-jre")

  // 3. Android - Use Guava in your implementation only:
  implementation("com.google.guava:guava:33.7.1-android")

  // 4. Android - Use Guava types in your public API:
  api("com.google.guava:guava:33.7.1-android")
}

For more information on when to use api and when to use implementation, consult the Gradle documentation on API and implementation separation.

Snapshots and Documentation

Snapshots of Guava built from the master branch are available through Maven using version 999.0.0-HEAD-jre-SNAPSHOT, or 999.0.0-HEAD-android-SNAPSHOT for the Android flavor.

Snapshot API Javadoc as well as Snapshot API Diffs are also available.

Another easy way to get to the Javadoc is to open guava.dev/api. You can also jump right to a specific class by appending the class name to guava.dev. For example, guava.dev/ImmutableList!

Learn about Guava

IMPORTANT WARNINGS

  1. APIs marked with the @Beta annotation at the class or method level are subject to change. They can be modified in any way, or even removed, at any time. If your code is a library itself (i.e., it is used on the CLASSPATH of users outside your own control), you should not use beta APIs unless you repackage them. If your code is a library, we strongly recommend using the Guava Beta Checker to ensure that you do not use any @Beta APIs!

  2. APIs without @Beta will remain binary-compatible for the indefinite future. (Previously, we sometimes removed such APIs after a deprecation period. The last release to remove non-@Beta APIs was Guava 21.0.) Even @Deprecated APIs will remain (again, unless they are @Beta). We have no plans to start removing things again, but officially, we're leaving our options open in case of surprises (like, say, a serious security problem).

  3. Guava has one dependency that is needed for linkage at runtime: com.google.guava:failureaccess:1.0.3. It also has some annotation-only dependencies, which we discuss in more detail at that link.

  4. Serialized forms of ALL objects are subject to change unless noted otherwise. Do not persist these and assume they can be read by a future version of the library.

  5. Our classes are not designed to protect against a malicious caller. You should not use them for communication between trusted and untrusted code.

  6. For the mainline flavor, we test the libraries using a range of OpenJDK versions on Linux and Windows. Some features, especially in com.google.common.io, may not work correctly in non-Linux environments. For the Android flavor, our unit tests also run on API level 24 (Nougat).

guava (google/guava)

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Guava
What is this?Guava is a set of core Java libraries from Google, providing new collection types (multimap, multiset), immutable collections, a graph library, and utilities for concurrency, I/O, hashing, primitives, and strings. It is heavily used inside Google and by many other companies.
Is this a framework or just a utility library?It's a utility library you add as a dependency, not a framework — there's no app lifecycle or runtime to adopt, just classes and helpers you call from your own code.
How do I add it to a project?Add Guava as a Maven or Gradle dependency using group ID com.google.guava and artifact ID guava, picking a version suffix for the flavor you need (e.g. 33.7.1-jre).
Which Java version or flavor do I need?The JRE flavor requires JDK 1.8 or higher; if you need Android support, use the Android flavor instead, which also runs its tests on API level 24 (Nougat).
Any pitfalls I should watch for with Guava's APIs?APIs marked @Beta can change or be removed at any time, so library authors should avoid them (or repackage them) unless they use the Guava Beta Checker; non-@Beta APIs, however, stay binary-compatible indefinitely.
Who typically uses Guava?It's aimed at Java developers who want battle-tested collection types and utilities; it's widely used inside Google itself and by many external companies.
Does Guava work the same on Windows as on Linux?Mostly yes, but some features—especially in com.google.common.io—may not behave correctly outside Linux; the mainline flavor is tested across OpenJDK versions on both Linux and Windows.
Is Guava safe to use with untrusted code?No — Guava's classes are not designed to defend against malicious callers, so they shouldn't be used as a boundary between trusted and untrusted code.
Does Guava have any runtime dependencies of its own?Yes, one: com.google.guava:failureaccess:1.0.3 is needed for linkage at runtime, plus some annotation-only dependencies discussed in the docs.
Can I rely on serialized Guava objects across versions?No — serialized forms of all Guava objects are subject to change unless explicitly noted otherwise, so you shouldn't persist them expecting future compatibility.
Where can I find full API documentation?Javadoc is available at guava.dev/api, and you can jump to a specific class directly, e.g. guava.dev/ImmutableList; there's also a users' guide called Guava Explained.
What happens to deprecated (non-Beta) APIs?They remain in the library indefinitely — Guava stopped removing non-@Beta APIs after version 21.0 and has no current plans to resume, aside from rare security exceptions.
What are similar projects?HikariCP, caffeine, Android-Universal-Image-Loader, fastjson, moejs, workflow, goose, deeplearning4j
Which topics is it in?collection, concurrency, data-structures, utility, java, backend, performance, android, apache-2.0, library, cross-platform, developer-tools
Creator
google
Size
1.4 GB
Stars
51.9K
Updated
CommitOct 14Releasev33.7.2Sep 29
Age
12y
Commits · 90 Days