According to the JavaDoc for JDK1.1.6, Class::getDeclaredFields() always
returns an array. If the class or interface defines no fields, an empty array is
returned. However, sometimes this method has been clearly observed to return
null. The tested platform ( Windows NT V4.0 SP3, also happens on Solaris 2.5.1)

Again, It is NOT returning an array of length 0, it is returning NULL (i.e. not returning an array of any size).

A related issue is that when the customer sees this, the class actually DOES have fields. So there are two problems:

1) Instead of returning an array of size 0, it returns NULL
2) It should be returning an array of size > 0.

The customer really isn't able to produce a "test case" per se. This failure is
intermittent and has very low frequency, occurring say once every few hundred
thousand calls.