Instantiation of JPopupMenu in headless mode started to cause NPE since approximately JDK9b22.
This problem is not observed with JDK8u5 for example.

The following code if run with JDK9b23 with -Djava.awt.headless=true

------------------------------------------------------------
public class JPM {
    public static void main(String[] args) {
        new javax.swing.JPopupMenu();
    }
}
------------------------------------------------------------

results in

Exception in thread "main" java.lang.NullPointerException
at javax.swing.RepaintManager.currentManager(RepaintManager.java:263)
at javax.swing.JComponent.repaint(JComponent.java:4802)
at java.awt.Component.repaint(Component.java:3372)
at javax.swing.JComponent.setBorder(JComponent.java:1802)
at javax.swing.LookAndFeel.installBorder(LookAndFeel.java:229)
at javax.swing.plaf.basic.BasicPopupMenuUI.installDefaults(BasicPopupMenuUI.java:102)
at javax.swing.plaf.basic.BasicPopupMenuUI.installUI(BasicPopupMenuUI.java:91)
at javax.swing.JComponent.setUI(JComponent.java:666)
at javax.swing.JPopupMenu.setUI(JPopupMenu.java:220)
at javax.swing.JPopupMenu.updateUI(JPopupMenu.java:229)
at javax.swing.JPopupMenu.<init>(JPopupMenu.java:194)
at javax.swing.JPopupMenu.<init>(JPopupMenu.java:179)
at JPM.main(JPM.java:3)


The following JCK9 tests fail due to this issue


api/javax_swing/JPopupMenu/descriptions.html#updateUI
api/javax_swing/JPopupMenu/descriptions.html#getAccessibleXXX
api/javax_swing/JPopupMenu/descriptions.html#insert
api/javax_swing/JPopupMenu/descriptions.html#Action
api/javax_swing/JPopupMenu/descriptions.html#GetXXXListeners
api/javax_swing/JPopupMenu/descriptions.html#getXXX
api/javax_swing/JPopupMenu/descriptions.html#Ctor
api/javax_swing/JPopupMenu/AccessibleJPopupMenu/index.html#AccessibleContext
api/javax_swing/plaf/PopupMenuUI/index.html#Ctor
api/javax_swing/JPopupMenu/AccessibleJPopupMenu/index.html#Ctor
api/javax_swing/JPopupMenu/Separator/index.html#Ctor
api/javax_swing/JPopupMenu/descriptions.html#add
api/javax_swing/JPopupMenu/descriptions.html#set_isXXX
api/javax_swing/JPopupMenu/descriptions.html#MenuListenerXXX


Reproduced with Windows and Solaris-sparcv9