I wrote the code in this repository to experiment with the Java8 dialect of Cucumber-JVM.

Running the project

To run the demonstration you just have to enter "mvn clean verify" in the project root directory.

Running on Oracle JDK8

Everything is working fine on Oracle's JDK8. The tests fail (as expected) with a PendingException:

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running soy.wimmer.CucumberIT

1 Scenarios (1 pending)
3 Steps (2 skipped, 1 pending)
0m0,231s

cucumber.api.PendingException: TODO: implement me
	at soy.wimmer.CucumberStepdefs.lambda$new$0(CucumberStepdefs.java:10)
	at ✽.Given I have some dummy code(cucumber/cucumber-java8.feature:7)

Tests run: 5, Failures: 0, Errors: 0, Skipped: 4, Time elapsed: 0.518 sec - in soy.wimmer.CucumberIT

Results :

Tests run: 4, Failures: 0, Errors: 0, Skipped: 3

Running on OpenJDK 1.8.0

When I run the same project on OpenJDK 1.8.0 it does not behave as expected. Running the test fails with an internal problem in Cucumber-Java8:

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running soy.wimmer.CucumberIT

0 Scenarios
0 Steps
0m0.000s

Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.056 sec <<< FAILURE! - in soy.wimmer.CucumberIT
Feature: Cucumber with Java8  Time elapsed: 0.047 sec  <<< ERROR!
cucumber.runtime.CucumberException: Failed to instantiate class soy.wimmer.CucumberStepdefs
[…]
Caused by: java.lang.reflect.InvocationTargetException: null
[…]
Caused by: cucumber.runtime.CucumberException: java.lang.IllegalArgumentException: Wrong type at constant pool index
[…]
Caused by: java.lang.IllegalArgumentException: Wrong type at constant pool index
	at sun.reflect.ConstantPool.getMemberRefInfoAt0(Native Method)
	at sun.reflect.ConstantPool.getMemberRefInfoAt(ConstantPool.java:47)
	at cucumber.runtime.java8.ConstantPoolTypeIntrospector.getTypeString(ConstantPoolTypeIntrospector.java:37)
	at cucumber.runtime.java8.ConstantPoolTypeIntrospector.getGenericTypes(ConstantPoolTypeIntrospector.java:27)
	at cucumber.runtime.java.Java8StepDefinition.<init>(Java8StepDefinition.java:45)
	at cucumber.runtime.java.JavaBackend.addStepDefinition(JavaBackend.java:162)
	at cucumber.api.java8.En.Given(En.java:190)
	at soy.wimmer.CucumberStepdefs.<init>(CucumberStepdefs.java:8)
[…]


Results :

Tests in error:
  Failed to instantiate class soy.wimmer.CucumberStepdefs

Tests run: 1, Failures: 0, Errors: 1, Skipped: 0

This is caused by .

Accessing a fixed position (second last element) in the constant pool seems to be the problem for the compatibility problem. There is no guaranty of any particular order of the items in there, and it seems that OpenJDK has a different order than Oracle's JDK.

Pointers

I had great help from user Holger at Stackoverflow (http://stackoverflow.com/users/2711488/holger) to understand this problem.

I posted this problem on Stackoverflow: http://stackoverflow.com/questions/32728342/always-getting-exception-wrong-type-at-constant-pool-index-with-cucumber-java8

I have opened an issue report here: cucumber/cucumber-jvm#912