$ used in RPGLE Java Prototype

Here are my questions - What does the $ mean when used in a java method prototype? Does it indicate an inner class? Where can I find the documentation (I looked, but could not find!)?

Here is why I ask...........

I was trying to prototype a method that returns an object that is a nested class.

This is what I initially tried. Focus on 'com.idx.hco.hpa.VisitFiler.PlanRecord' .

d getPlanRecordByCode...
d pr o ExtProc(*JAVA:
d 'com.idx.hco.hpa.VisitFiler'
d :'getPlanRecordByCode')
d CLASS(*JAVA:
d 'com.idx.hco.hpa.VisitFiler-
d .PlanRecord')
d str like(jString) const

I kept getting the"NoSuchMethodError".

After much head banging, I used javap to look at the expected signature and found it was showing this - 'com.idx.hco.hpa.VisitFiler$PlanRecord'

Grasping at straws, I changed my prototype accordingly and it worked!

d getPlanRecordByCode...
d pr o ExtProc(*JAVA:
d 'com.idx.hco.hpa.VisitFiler'
d :'getPlanRecordByCode')
d CLASS(*JAVA:
d 'com.idx.hco.hpa.VisitFiler-
d $PlanRecord')
d str like(jString) const

Thanks,

Joe