The following test failed in the JDK16 CI:

sanity/client/SwingSet/src/FrameDemoTest.java

Here's a snippet from the log file:

Wait frame to have 0 state
    : javax.swing.JFrame[frame1,167,68,300x272,invalid,layout=java.awt.BorderLayout,title=Demo JFrame,resizable,maximized,defaultCloseOperation=HIDE_ON_CLOSE,rootPane=javax.swing.JRootPane[,0,37,300x235,invalid,layout=javax.swing.JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true]
disposeAllWindows
test FrameDemoTest.test("javax.swing.plaf.metal.MetalLookAndFeel"): failure
org.netbeans.jemmy.TimeoutExpiredException: Wait "0 state" state to be reached (ComponentOperator.WaitStateTimeout)
at org.netbeans.jemmy.Waiter.waitAction(Waiter.java:210)
at org.netbeans.jemmy.operators.Operator.waitState(Operator.java:721)
at org.netbeans.jemmy.operators.Operator.waitState(Operator.java:696)
at org.netbeans.jemmy.operators.FrameOperator.waitState(FrameOperator.java:309)
at org.netbeans.jemmy.operators.FrameOperator.deiconify(FrameOperator.java:268)
at FrameDemoTest.checkFrameActions(FrameDemoTest.java:191)
at FrameDemoTest.test(FrameDemoTest.java:122)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:85)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:639)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:821)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1131)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:124)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:108)
at org.testng.TestRunner.privateRun(TestRunner.java:773)
at org.testng.TestRunner.run(TestRunner.java:623)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:357)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:352)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:310)
at org.testng.SuiteRunner.run(SuiteRunner.java:259)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1185)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1110)
at org.testng.TestNG.run(TestNG.java:1018)
at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:94)
at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:54)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)
Trace:
Start to wait frame "Frame with title "JFrame Demo"" opened