First, let's get Retrolambda set up. We will also leverage a quick unit test to see whether it works correctly.
Open the ExampleUnitTest.java file that was created with the project template under app/java/com/packtpub/rxjavaapp, as shown in the following screenshot:
Remove the sample unit test method inside it and declare a new one called lambdaTest() as follows:
Note that it throws a compiler error because we are not using Java 8 to support lambdas. If you navigate to the lambda expression, you will see the error message ...
