Immutable Collections

There are a few classes that are truly immutable (not like those pseudo immutables from Guava and Apache Commons):

• Array: implements Collection;
• ArraySet: implements Set;
• ArraySortedSet: implements SortedSet;
• ArrayMap: implements Map.

All of them are annotated with @Immutable.

The only dependency you need is (you can also download jcabi-immutable-1.5.0.jar and add it to the classpath):

<dependency>
  <groupId>com.jcabi</groupId>
  <artifactId>jcabi-immutable</artifactId>
  <version>1.5.0</version>
</dependency>

Limitation

Encapsulated objects with exposed mutators can mutate their state.

<repositories>
  <repository>
    <id>oss.sonatype.org</id>
    <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
  </repository>
</repositories>
<dependencies>
  <dependency>
    <groupId>com.jcabi</groupId>
    <artifactId>jcabi-immutable</artifactId>
    <version>2.0-SNAPSHOT</version>
  </dependency>
</dependencies>