Jackson 2.7.1 doesn't work with jdk6 due to use of `Collections.emptyIterator()`

[saladinkzn]

Collections.emptyIterator() is not available on jdk6:

java.lang.IllegalAccessError: tried to access method java.util.Collections.emptyIterator()Ljava/util/Iterator; from class com.fasterxml.jackson.databind.util.ClassUtil
        at com.fasterxml.jackson.databind.util.ClassUtil.emptyIterator(ClassUtil.java:24)
        at com.fasterxml.jackson.databind.introspect.POJOPropertyBuilder.getConstructorParameters(POJOPropertyBuilder.java:383)
        at com.fasterxml.jackson.databind.deser.BasicDeserializerFactory._findCreatorsFromProperties(BasicDeserializerFactory.java:331)
        at com.fasterxml.jackson.databind.deser.BasicDeserializerFactory._constructDefaultValueInstantiator(BasicDeserializerFactory.java:312)
        at com.fasterxml.jackson.databind.deser.BasicDeserializerFactory.findValueInstantiator(BasicDeserializerFactory.java:252)
        at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.buildBeanDeserializer(BeanDeserializerFactory.java:221)
        at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.createBeanDeserializer(BeanDeserializerFactory.java:143)
        at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer2(DeserializerCache.java:406)
        at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer(DeserializerCache.java:352)
        at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:264)
        at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:244)
        at com.fasterxml.jackson.databind.deser.DeserializerCache.hasValueDeserializerFor(DeserializerCache.java:191)
        at com.fasterxml.jackson.databind.DeserializationContext.hasValueDeserializerFor(DeserializationContext.java:422)
        at com.fasterxml.jackson.databind.ObjectMapper.canDeserialize(ObjectMapper.java:2633)
        at ru.shadam.ferry.simple.responsehandler.ObjectMapperResponseHandlerFactory.canCreateExtractor(ObjectMapperResponseHandlerFactory.java:25)
        at ru.shadam.ferry.factory.result.CompositeResultExtractorFactory.getResultExtractor(CompositeResultExtractorFactory.java:33)
        at ru.shadam.ferry.factory.InvocationHandlerFactory.getMethodExecutionContext(InvocationHandlerFactory.java:84)
        at ru.shadam.ferry.factory.InvocationHandlerFactory.createInvocationHandler(InvocationHandlerFactory.java:76)
        at ru.shadam.ferry.factory.ClientImplementationFactory.getInterfaceImplementation(ClientImplementationFactory.java:39)

[saladinkzn]

Well, maybe it's not actually an issue as you stated that 2.7.x has jdk7 base line

But this quote:

So it should still be possible to use Jackson 2.7 on Java 6, but not compile, build.

Is not true.

[cowtowncoder]

@saladinkzn Thank you for reporting this. Usage is accidental and is indeed contradicting the statement. Simple compatibility testing I tried managed to not notice this problem unfortunately. Will try to fix this for 2.7.2.

[cowtowncoder]

Thank you for reporting this; issue fixed in 2.7.2. Please let me know if you uncover other similar issues.
I hope to figure out a better way to test for compatibility wrt JDK6.