FULL PRODUCT VERSION :
JDK under test: /usr/local/java/jdk1.8.0_131
java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
$ uname -a
Linux localhost.localdomain 4.10.10-200.fc25.x86_64 #1 SMP Thu Apr 13 01:11:51 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ cat /etc/fedora-release
Fedora release 25 (Twenty Five)



A DESCRIPTION OF THE PROBLEM :
The test javax/swing/Popup/TaskbarPositionTest.java intermittently fails on Fedora 25 with the message "java.lang.RuntimeException: We do not match! java.awt.Rectangle[x=0,y=27,width=1360,height=741] / java.awt.Rectangle[x=0,y=0,width=0,height=0]"


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
$ jtreg -ignore:quiet -v -a -xml -javaoptions:'-Djava.awt.headless=false' -timeoutFactor:2 javax/swing/Popup/TaskbarPositionTest.java


ERROR MESSAGES/STACK TRACES THAT OCCUR :
#section:main
----------messages:(4/139)----------
command: main TaskbarPositionTest
reason: User specified action: run main TaskbarPositionTest
Mode: othervm
elapsed time (seconds): 0.948
----------configuration:(0/0)----------
----------System.out:(0/0)----------
----------System.err:(14/1090)----------
java.lang.RuntimeException: We do not match! java.awt.Rectangle[x=0,y=27,width=1360,height=741] / java.awt.Rectangle[x=0,y=0,width=0,height=0]
    at TaskbarPositionTest.isPopupOnScreen(TaskbarPositionTest.java:165)
    at TaskbarPositionTest.main(TaskbarPositionTest.java:279)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:115)
    at java.lang.Thread.run(Thread.java:745)

JavaTest Message: Test threw exception: java.lang.RuntimeException: We do not match! java.awt.Rectangle[x=0,y=27,width=1360,height=741] / java.awt.Rectangle[x=0,y=0,width=0,height=0]
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: We do not match! java.awt.Rectangle[x=0,y=27,width=1360,height=741] / java.awt.Rectangle[x=0,y=0,width=0,height=0]
----------rerun:(21/1769)*----------
DISPLAY=:0 \\
GNOME_DESKTOP_SESSION_ID=this-is-deprecated \\
HOME=/home/vprovodin \\
LANG=en_US.UTF-8 \\
PATH=/bin:/usr/bin \\
XMODIFIERS=@im=ibus \\
CLASSPATH=/home/vprovodin/workspace/github/jdk8u/jdk/JTwork/classes/javax/swing/Popup:/home/vprovodin/workspace/github/jdk8u/jdk/test/javax/swing/Popup:/home/vprovodin/workspace/github/jdk8u/jdk/JTwork/classes/javax/swing/regtesthelpers:/home/vprovodin/workspace/github/jdk8u/jdk/test/javax/swing/regtesthelpers:/home/vprovodin/workspace/jdk/jbsdk8u112b736.21_x64/lib/tools.jar:/home/vprovodin/workspace/jtreg/lib/javatest.jar:/home/vprovodin/workspace/jtreg/lib/jtreg.jar \\
    /home/vprovodin/workspace/jdk/jbsdk8u112b736.21_x64/bin/java \\
        -Dtest.src=/home/vprovodin/workspace/github/jdk8u/jdk/test/javax/swing/Popup \\
        -Dtest.src.path=/home/vprovodin/workspace/github/jdk8u/jdk/test/javax/swing/Popup:/home/vprovodin/workspace/github/jdk8u/jdk/test/javax/swing/regtesthelpers \\
        -Dtest.classes=/home/vprovodin/workspace/github/jdk8u/jdk/JTwork/classes/javax/swing/Popup \\
        -Dtest.class.path=/home/vprovodin/workspace/github/jdk8u/jdk/JTwork/classes/javax/swing/Popup:/home/vprovodin/workspace/github/jdk8u/jdk/JTwork/classes/javax/swing/regtesthelpers \\
        -Dtest.vm.opts= \\
        -Dtest.tool.vm.opts= \\
        -Dtest.compiler.opts= \\
        -Dtest.java.opts=-Djava.awt.headless=false \\
        -Dtest.jdk=/home/vprovodin/workspace/jdk/jbsdk8u112b736.21_x64 \\
        -Dcompile.jdk=/home/vprovodin/workspace/jdk/jbsdk8u112b736.21_x64 \\
        -Dtest.timeout.factor=2.0 \\
        -Djava.awt.headless=false \\
        com.sun.javatest.regtest.agent.MainWrapper /home/vprovodin/workspace/github/jdk8u/jdk/JTwork/javax/swing/Popup/TaskbarPositionTest_id0.d/main.0.jta
result: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: We do not match! java.awt.Rectangle[x=0,y=27,width=1360,height=741] / java.awt.Rectangle[x=0,y=0,width=0,height=0]


test result: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: We do not match! java.awt.Rectangle[x=0,y=27,width=1360,height=741] / java.awt.Rectangle[x=0,y=0,width=0,height=0]

REPRODUCIBILITY :
This bug can be reproduced often.