ADDITIONAL SYSTEM INFORMATION :
$ uname -a
Darwin unit 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 x86_64

JDK under test: /Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home
java version "11.0.1" 2018-10-16 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)


A DESCRIPTION OF THE PROBLEM :
The test java/awt/Robot/HiDPIScreenCapture/ScreenCaptureTest.java fails on MacOSX, Windows. This failure was also observed on Kubuntu (KDE)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
$ jtreg -ignore:quiet -v -a -xml -testjdk:/Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home/ java/awt/Robot/HiDPIScreenCapture/ScreenCaptureTest.java

ACTUAL -
#section:main
----------messages:(5/270)----------
command: main -Dsun.java2d.uiScale=1 ScreenCaptureTest
reason: User specified action: run main/othervm -Dsun.java2d.uiScale=1 ScreenCaptureTest
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.desktop
elapsed time (seconds): 1.55
----------configuration:(3/40)----------
Boot Layer
  add modules: java.desktop

----------System.out:(0/0)----------
----------System.err:(13/849)----------
java.lang.RuntimeException: Wrong Pixel Color! Expected GREEN
at ScreenCaptureTest.main(ScreenCaptureTest.java:93)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:115)
at java.base/java.lang.Thread.run(Thread.java:834)

JavaTest Message: Test threw exception: java.lang.RuntimeException: Wrong Pixel Color! Expected GREEN
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: Wrong Pixel Color! Expected GREEN

---------- BEGIN SOURCE ----------
http://hg.openjdk.java.net/jdk/jdk11/file/1ddf9a99e4ad/test/jdk/java/awt/Robot/HiDPIScreenCapture/ScreenCaptureTest.java
---------- END SOURCE ----------

FREQUENCY : always