I was getting the same error:
"Handler processing failed; nested exception is
java.lang.IllegalAccessError: tried to access method
org.apache.poi.util.POILogger.log(ILjava/lang/Object;)V from class
org.apache.poi.openxml4j.opc.PackageRelationshipCollection"
After updating maven and trying to access PackageRelationshipCollection and POILogger classes in eclipse things worked fine for me. Make sure you have all the required jars i.e poi, poi-ooxml, poi-ooxml-schemas.
