The following 10 tests failed in the JDK16 CI:

javax/swing/text/DefaultCaret/HidingSelection/HidingSelectionTest.java
javax/swing/text/CSSBorder/6796710/bug6796710.java
javax/swing/JWindow/ShapedAndTranslucentWindows/ShapedTranslucentPerPixelTranslucentGradient.java
javax/swing/JWindow/ShapedAndTranslucentWindows/ShapedPerPixelTranslucentGradient.java
java/awt/image/multiresolution/MultiResolutionJOptionPaneIconTest.java
java/awt/image/multiresolution/MenuMultiresolutionIconTest.java
java/awt/GraphicsDevice/DisplayModes/CycleDMImage.java
java/awt/FullScreen/FullScreenInsets/FullScreenInsets.java
java/awt/Frame/InvisibleOwner/InvisibleOwner.java
java/awt/ColorClass/AlphaColorTest.java

The tests failed for a variety of reasons and I don't see any
obviously common reason for the failures. However, I really
don't want to file 10 individual bugs in client-libs.