Hadoop Java MapReduce parsing JSON with Jackson issues
This might be due to class loading problems: old version of jackson core or so.The tricky part wrt class loading and annotations is that VM is apparently allowed to just drop annotations it does not recognize. I don't know if this could be causing problem you have, but it may be worth checking. Hadoop used to bundle rather old version of Jackson (1.1?), and since @JsonIgnoreProperties was added in 1.4, this might explain the problem.
How could this occur? You must be compiling using a more recent version (to see the annotation), but perhaps runtime environment is using old (1.1) version. Because you do not actively use annotation class from your code (it is "only" associated with the class), class loader would then drop this annotation as it can not find it from jar.