Difference in running Cucumber-JVM vs Cucumber runner(Junit) - junit

Question

I am fairly new to Cucumber. I was experimenting with it by just creating few test features when I noticed the difference when running a single feature vs running the whole suite (from the IntelliJ).
I noticed that when I run single feature it runs using the cucumber-jvm option and in this case, the CucumberConfig(the blank class to define the runner and cucumber options) and the Runner is not utilized. However, when I run the whole suite it runs as a JUnit test and obviously, in this case, the Config class and the runner comes into the picture.
I confirmed this with the following sample code:
#RunWith(CustomRunner.class)
#CucumberOptions()
public class CucumberConfig {
#BeforeClass
public static void beforeClass()
{
System.out.println("This is run before Once: ");
}
#AfterClass
public static void afterClass()
{
System.out.println("This is run after Once: ");
}
}
CustomRunner
public class CustomRunner extends Cucumber {
public CustomRunner(Class clazz) throws InitializationError, IOException {
super(clazz);
System.out.println("I am in the custom runner.");
}
}
Also, I understand that while running as cucumber-junit we can't pass specific feature to run as in cucumber-jvm. Correct me if I am wrong.
My doubt is, is this the default behavior or am I doing something wrong. And, if this is default how can I make cucumber to always use the Config file.
I'll appreciate if someone can provide some insight on this.

Answer 1

When you're using IntelliJ IDEA to run the tests, IDEA will use cucumber.api.Main to run the tests. As such it will ignore CucumberConfig neither will it run #BeforeClass nor #AfterClass, these are only used by the JUnit runner.