Using Scala libraries from Java 8 can be difficult, because Scala's functions are traits, and not recognised as a FunctionalInterface by the Java compiler. Sc8 is a simple conversion library that converts Java lambdas to Scala functions.

<dependency>
  <groupId>com.github.eirslett</groupId>
  <artifactId>sc8</artifactId>
  <version>0.1.0</version>
</dependency>

In your Java file, import F (and/or C if required):

import static com.github.eirslett.sc8.Sc8.C;
import static com.github.eirslett.sc8.Sc8.F;

What you have to do, is to wrap your lambda with F(...), for example:

result = someList.map(F(s -> s.toUpperCase()));

The F function converts the lambda into a Scala function for you. If your lambda returns void, use C instead:

myFuture.onSuccess(C(s -> System.out.println(s)));

Look at the tests for more examples.

You need Java 8 and Maven to build this project. (Get Java 8 here: https://jdk8.java.net/download.html)

$ mvn clean package

If you don't want to install jdk8 globally, you can put it in a folder "jdk1.8.0" inside this project, and build with the "localjdk" profile:

$ mvn clean package -Plocaljdk

The Java and Scala sources are for the most part auto-generated, by the PHP-script "genfuncs.php". To generate sources, you will need PHP. Run $ php genfuncs.php to generate.