Guava is a set of core libraries that includes new collection types (such as multimap and multiset), immutable collections, a graph library, functional types, an in-memory cache, and APIs/utilities for concurrency, I/O, hashing, primitives, reflection, string processing, and much more!

Requires JDK 1.8 or higher. If you need support for JDK 1.6 or Android, use 20.0 for now. In the next release (22.0) we will begin providing a backport for use on Android and lower JDK versions.

The most recent release is Guava 21.0, released January 12, 2017.

• 21.0 API Docs: guava, guava-testlib
• 21.0 API Diffs from 20.0: guava

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

<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>21.0</version>
</dependency>

To add a dependency using Gradle:

dependencies {
  compile 'com.google.guava:guava:21.0'
}

Snapshots of Guava built from the master branch are available through Maven using version 22.0-SNAPSHOT.

• Snapshot API Docs: guava
• Snapshot API Diffs from 21.0: guava

• Our users' guide, Guava Explained
• A nice collection of other helpful links

• GitHub project
• Issue tracker: Report a defect or feature request
• StackOverflow: Ask "how-to" and "why-didn't-it-work" questions
• guava-discuss: For open-ended questions and discussion

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 (e.g. using ProGuard).

2. Deprecated non-beta APIs will be removed two years after the release in which they are first deprecated. You must fix your references before this time. If you don't, any manner of breakage could result (you are not guaranteed a compilation error).

3. 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.

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

5. We unit-test and benchmark the libraries using only OpenJDK 1.8 on Linux. Some features, especially in com.google.common.io, may not work correctly in other environments.