This has come up before and been blocked on the fact that Tiltyard is a major consumer of GGP-Base as a library, and it uses Google App Engine, which still doesn't have Java 8 support.
Given that, it's now worth tracking this in its own ticket.
(Note that in the meantime, if you have your own checkout of GGP-Base and want to use Java 8, you should feel free to modify the sourceCompatibility and targetCompatibility in build.gradle to 1.8 and regenerate your IDE files with e.g. ./gradlew eclipse or ./gradlew idea. This should enable you to use Java 8 language features.)
This has come up before and been blocked on the fact that Tiltyard is a major consumer of GGP-Base as a library, and it uses Google App Engine, which still doesn't have Java 8 support.
However, the Google App Engine team has announced that they will be supporting Java 8 in the next few months: https://cloudplatform.googleblog.com/2017/03/your-favorite-languages-now-on-Google-App-Engine.html
Given that, it's now worth tracking this in its own ticket.
(Note that in the meantime, if you have your own checkout of GGP-Base and want to use Java 8, you should feel free to modify the sourceCompatibility and targetCompatibility in build.gradle to 1.8 and regenerate your IDE files with e.g.
./gradlew eclipse
or./gradlew idea
. This should enable you to use Java 8 language features.)