A curious developer might have heard about new Java 8 features, such as lambdas and method references. However, they are not available by default on the Android platform.
At the moment, there are three ways to add some of the Java 8 features on the platform. One of them is the new Jack compiler, but it is now deprecated. The other option is to rely on the new Java 8 features that will be released sometime soon in the default toolchain (at the time of writing, Java 8 support was in the preview).