streamsupport is a backport of the Java 8 java.util.function (functional interfaces) and java.util.stream (streams) API for Android and users of Java 6 or 7 supplemented with selected additions from java.util.concurrent which didn't exist back in Java 6.

Due to the lack of default interface methods and static interface methods in pre-Java 8 the API had to be slightly adjusted in these areas but still covers the full functionality scope of Java 8. In detail, static and default interface methods have been moved to companion classes in the same package that bear the identical name as the interface but with an "s" appended (e.g. Comparator -> Comparators).

For ease of use, the default methods for most of the functional interfaces were NOT retained as abstract methods in the redefined interfaces (keeping them single method interfaces) - the missing default (and static) methods can always be found in the corresponding companion class.

The streamsupport API lives in the packages java8.util.* and java8.lang respectively. So, it's not possible to simply import the java.util.stream package in your code - you'd rather have to use java8.util.stream instead (see Readme.txt for details). While that is fine as long as you have full control over your source code there is the other common scenario of using a binary 3rd party dependency that has been compiled against the standard Java 8 java.util.stream API. In the latter case bytecode rewriting via ProGuard might be an option. ProGuard supports most Java 8 language features and the latest release can also replace the standard Java 8 stream API by the the streamsupport backport (cf. the Proguard documentation, especially the section titled "Java 8 stream API support").

The current stable release of streamsupport is streamsupport-1.7.2.

Want also lambdas? https://github.com/orfjackal/retrolambda

Note that the streamsupport sourceforge site has been discontinued. New developments, if any, will take place here.

Please give feedback here if you experience any problems.

• Java 8 / Java 9 Streams library backport
• Java 8 / Java 9 CompletableFuture backport
• Java 8 Parallel array operations backport
• Java 8 Functional interfaces backport
• Further java.util.concurrent enhancements from Java 7/8 backported to Java 6
• Includes miscellaneous Java 8 / Java 9 goodies (Optional, StringJoiner, ...)
• Supports Android - all versions, starting from Ice Cream Sandwich

dependencies {
    implementation 'net.sourceforge.streamsupport:streamsupport:1.7.2'
}

<dependency>
    <groupId>net.sourceforge.streamsupport</groupId>
    <artifactId>streamsupport</artifactId>
    <version>1.7.2</version>
</dependency>

import java.util.List;
import java8.util.stream.IntStreams;
import java8.util.stream.StreamSupport;
import static java8.util.stream.Collectors.toList;

List<Integer> list = IntStreams.of(1, 2, 3, 4).boxed()
        .collect(toList());

List<Integer> incremented = StreamSupport.stream(list)
        .map(i -> i + 1)
        .collect(toList());

Android developers using the Android Studio 3.x toolchain should have a look at the streamsupport forks:

• android-retrostreams
• android-retrofuture
• android-retroflow
• android-retroatomic

Release Notes

GNU General Public License, version 2, with the Classpath Exception