ArrayIndexOutOfBoundsException

[chanjarster]

Steps to reproduce

JaCoCo version: 0.8.2
Operating system: "mac os x", version: "10.14.2", arch: "x86_64", family: "mac"
Tool integration: Maven 3.5.4
Java version: java version "1.8.0_181"

1. Have docker installed.
2. Use the reproducible code: https://github.com/chanjarster/jacoco-array-index-out-of-bounds-bug
3. Maven command: mvn clean install

Expected behaviour

Everything goes fine.

Actual behaviour

Maven result:

[ERROR] Failures:
[ERROR] me.chanjar.jacocobug.system.repo.DictionaryTypeRepositoryIT.testDictionaryTypeSort(me.chanjar.jacocobug.system.repo.DictionaryTypeRepositoryIT)
[INFO]   Run 1: PASS
[ERROR]   Run 2: DictionaryTypeRepositoryIT>AbstractTestNGSpringContextTests.run:180->testDictionaryTypeSort:31 » ArrayIndexOutOfBounds

Failsafe report:

testDictionaryTypeSort (me.chanjar.jacocobug.system.domain.DictionaryType@4057fa5f)
java.lang.ArrayIndexOutOfBoundsException: 23
	at me.chanjar.jacocobug.system.domain.DictionaryType.setIsDataCenter(DictionaryType.java:100)
	at me.chanjar.jacocobug.system.repo.DictionaryTypeRepository.createDictionaryType(DictionaryTypeRepository.java:42)
	at me.chanjar.jacocobug.system.repo.DictionaryTypeRepository$$FastClassBySpringCGLIB$$9d92e7db.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:746)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688)
	at me.chanjar.jacocobug.system.repo.DictionaryTypeRepository$$EnhancerBySpringCGLIB$$7ea2705b.createDictionaryType(<generated>)
	at me.chanjar.jacocobug.system.repo.DictionaryTypeRepositoryIT.testDictionaryTypeSort(DictionaryTypeRepositoryIT.java:31)
	at org.springframework.test.context.testng.AbstractTestNGSpringContextTests.run(AbstractTestNGSpringContextTests.java:180)
... Removed 32 stack frames

I suspect this bug related to reflection. If I comment out this line, no problem shows.

[marchof]

The code clearly shows that this is the problem described in our FAQ:

My code uses reflection. Why does it fail when I execute it with JaCoCo?

To collect execution data JaCoCo instruments the classes under test which adds two members to the classes: A private static field $jacocoData and a private static method $jacocoInit(). Both members are marked as synthetic.

Please change your code to ignore synthetic members. This is a good practice anyways as also the Java compiler creates synthetic members in certain situation.

Your example code iterates over all fields (including static and synthetic) ones.

[chanjarster]

@marchof Wow, that's crystal clear, this problem bother me several days, thanks.