[macosx] The Choice List can't work correctly.

Testsuite name:JCK manual
Test name:api/java_awt/interactive/ChoiceTests.html#ChoiceTests
Product tested: JDK 9 b71(64bit)
OS/architecture:Mac10.10-x64 (Processor:3.06 GHz Intel Core i3;Memory:4 GB 1333 MHz DDR3)
 
Error log file:http://aurora-ds3.us.oracle.com:9502/runs/00991/991913.ManualSubmit/991913.ManualSubmit-1/workDir/api/java_awt/interactive/ChoiceTests_ChoiceTests.jtr

Reproducible: Always
Reproducible on machine: Evergreen-machine
[If Sometimes] Also reproducible on machine:

Is it a Regression: Yes
[If Regression] Regression introduced in release/build:JDK9b68(64bit) Failed,but JDK9b67(64bit) on same platform Passed.
Test result on the last GAed release for this train:
[if Fail] Test result on FCS:

Is it a platform specific issue:Yes
 (same build on win7-p1-x64 Passed,
 same build on oel6.4-x64 Passed,
 same build on solaris11.2-x64 Passed,
 same build on solaris11-sparc Passed)
Is it a new (previously unsupported) OS/browser/mode testing: No
[If new configuration testing] Issue specific to execution mode or OS/browser version:

Exception from Log:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at sun.lwawt.macosx.LWCToolkit.getScreenInsets(LWCToolkit.java:411)
at com.apple.laf.AquaComboBoxPopup.getBestScreenBounds(AquaComboBoxPopup.java:207)
at com.apple.laf.AquaComboBoxPopup.computePopupBounds(AquaComboBoxPopup.java:249)
at com.apple.laf.AquaComboBoxPopup.adjustPopupAndGetBounds(AquaComboBoxPopup.java:170)
at com.apple.laf.AquaComboBoxPopup.show(AquaComboBoxPopup.java:124)
at javax.swing.plaf.basic.BasicComboPopup.togglePopup(BasicComboPopup.java:1200)
at javax.swing.plaf.basic.BasicComboPopup$Handler.mousePressed(BasicComboPopup.java:881)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:288)
at java.awt.Component.processMouseEvent(Component.java:6600)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3349)
at java.awt.Component.processEvent(Component.java:6368)
at java.awt.Container.processEvent(Container.java:2259)
at java.awt.Component$1.processEvent(Component.java:966)
at sun.lwawt.LWComponentPeer.sendEventToDelegate(LWComponentPeer.java:1213)
at sun.lwawt.LWComponentPeer.handleEvent(LWComponentPeer.java:1202)
at java.awt.Component.dispatchEventImpl(Component.java:5048)
at java.awt.Component.dispatchEvent(Component.java:4819)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:761)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:712)
at java.awt.EventQueue$3.run(EventQueue.java:706)
......


Steps to reproduce:
1. Install test bundle jdk9b71 from http://jre.us.oracle.com/java/re/jdk/9/promoted/all/b71/bundles/macosx-x86_64/jdk-9-ea-macosx-x64.dmg to /Library/Java/JavaVirtualMachines/
2. Download the JCK-runtime-9.jar from http://jre.us.oracle.com/java/re/jck/9/promoted/latest/bundles/ to /var/root/workspace/jck/ and use /Library/Java/JavaVirtualMachines/jdk1.9.0.jdk/Contents/Home/bin/java -jar JCK-runtime-9.jar to unzip it
3.Run the following command:
/Library/Java/JavaVirtualMachines/jdk1.9.0.jdk/Contents/Home/bin/java -showversion -cp /private/var/root/workspace/jck/JCK-runtime-9/classes:/Library/Java/JavaVirtualMachines/jdk1.9.0.jdk/Contents/Home -Djava.security.policy=/private/var/root/workspace/jck/JCK-runtime-9/lib/jck.policy javasoft.sqe.tests.api.java.awt.interactive.ChoiceTests -TestCaseID ALL

Descriptions:
Shown below on the left is a choice list.The "Add" operation which performs like an append requires a name to be specified.Please verify that the choice list is updated accordingly,and the status presented in the Status area is correct.

Actual behavior:
The drop-down can't be shown when we click the choice list,and exception throws out in the terminal.refer to ChoiceTest.jpg and ChoiceTest-right.jpg.

Validation:
JDK9b67(64bit) on same platform Passed.
JDK9b68(64bit) on same platform Failed.
JDK9b69(64bit) on same platform Failed.
JDK9b70(64bit) on same platform Failed.