In org.apache.abdera.parser.stax.util.FOMExtensionIterator(abdera code), it need use a field currentChild which inherit from org.apache.axiom.om.impl.traverse.OMAbstractIterator(axiom code), but field currentChild was removed from axiom 1.2.12, so that we can see exception like
java.lang.NoSuchFieldError: currentChild
at org.apache.abdera.parser.stax.util.FOMExtensionIterator.hasNext(FOMExtensionIterator.java:74)
at org.apache.abdera.parser.stax.util.FOMList.buffer(FOMList.java:60)
at org.apache.abdera.parser.stax.util.FOMList.size(FOMList.java:77)

As abdera 1.1.2 already the latest version so that I think we need rollback to axiom 1.2.10 utill next abdera version which can work with axiom 1.2.12

we have axiom 1.2.12 and abdera 1.1.2 together in features.xml for a long time, even in the FUSE ESB 4.4.x, but seems our customer didn't run into this error yet, AFAIK, this only happen when use atom related staff, like jax-rs atom provider or camel-atom feature.