This project contains several exercises to strengthen your skills with
functional programming, particularly as manifest in higher-order
functions and Java's Streams library.
The exercises can all be found in HigherOrderFunctionsLearningTest.
As the name implies, these are not proper unit tests because they test no
unit of production code; rather, they are learning tests, using the
JUnit framework to explore our understanding of the language and libraries.
From within IntelliJ IDEA, right-click on the test/java folder,
and choose to run all the tests. Keep in mind that you can also
run the tests through the debugger so that you can watch variables,
evaluate expressions, etc.
The tests use two data files. Both contain change data from
Wikipedia's Soup Page.
The number of changes in each file is encoded in the suffix:
soup04.json contains four changes, and soup30.json contains 30.
This Java project is powered by Gradle. Sometimes, Gradle and IntelliJ IDEA can get out of sync. If the project is showing false-positive compiler errors, try the following:
-
Open the Settings, navigate to the Gradle tab, and make sure that Gradle is being run through JDK15. This will fix the problem where Gradle fails to start because of an older default version of the JVM being installed.
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Open the Project Structure, change the language level to something like 1.8, apply the settings, then change the language level back to 15. This will force a recompile that will often fix the problem.