FULL PRODUCT VERSION :
java version "1.8.0_66"

ADDITIONAL OS VERSION INFORMATION :
Linux Mint 17.2

A DESCRIPTION OF THE PROBLEM :
After release 51, a bug appeared in the Nimbus L&F -- the scroll thumb disappeared. Scrolling was still possible, but it was necessary to hunt for the region where the scroll thumb ought to be. This is still true.

One remedy is to change L&Fs, but this is obviously not always possible. This is a severe bug.

This is not a new bug, but I'm reporting it to make you aware how serious it is and how it seems not to have been fixed in multiple updates. 

REGRESSION.  Last worked in version 8u51

ADDITIONAL REGRESSION INFORMATION: 
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b17, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run any Java application that uses the Nimbus L&F. Open a display that requires a scroll pane, and that has a document larger than the physical screen. Notice the absence of the scroll thumb.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Scrollbar thumb appears.
ACTUAL -
No scrollbar thumb.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Remove any release > 51, reinstall 51.