This test, javax/swing/plaf/metal/MetalGradient/8163193/ButtonGradientTest.java, fails on Windows 10 and Ubuntu Unity, Xfce4 with
 java.lang.RuntimeException: Button gradient is changed!
which precisely is fixed in 8163193 as I understand.

Adding some printout (BTW I don't know if it is useful or not but if it is, why not add it to the test forever?), we see e.g. on Xfce
  buttonColor: java.awt.Color[r=230,g=238,b=246]
gradientColor: java.awt.Color[r=237,g=243,b=248]

RULE "javax/swing/plaf/metal/MetalGradient/8163193/ButtonGradientTest.java" Exception java.lang.RuntimeException: Button gradient is changed!