Java programs won't start when external screen is set as main
 

The problem:

With the plugged docking station via USB-C, with an external monitor connected (hdmi or display port, happens with different kind of monitors), if I relocate the menu bar to the external monitor - I’ve noticed that I cannot open some softwares (like the last version of SQL Developer, some jar applications like FakeSMTP v2.0, …).
These softwares does not show any launcher and closes instantly without any error.


If I change back the menu bar to the the MacBook Pro’s monitor, these software opens without any problem.
If I connect the external monitor by using other kind of USB-C adapters, this problem does not happen when the menu bar is placed on the external monitor.


- I’ve tried to reinstall SQL Developer and the other softwares, but nothing changes.

- To run Fake SMTP 2.0 usually I have only to double click on the jar file. But it closes instantly. I’ve tried to run it from terminal with "java -jar”, and this error message appears:

05 Aug 2020 10:40:26 ERROR com.nilhcem.fakesmtp.core.exception.UncaughtExcept ionHandler -
java.lang.NullPointerException: null
at java.awt.Window.init(Window.java:497) ~[na:1.8.0_131]
at java.awt.Window.<init>(Window.java:537) ~[na:1.8.0_131]
at java.awt.Frame.<init>(Frame.java:420) ~[na:1.8.0_131]
at javax.swing.JFrame.<init>(JFrame.java:233) ~[na:1.8.0_131]
at com.nilhcem.fakesmtp.gui.MainFrame.<init>(MainFram e.java:25) ~[fakeSMTP-2.0.jar:na]
at com.nilhcem.fakesmtp.FakeSMTP$1.run(FakeSMTP.java: 97) ~[fakeSMTP-2.0.jar:na]
at java.awt.event.InvocationEvent.dispatch(Invocation Event.java:311) ~[na:1.8.0_131]
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:756) ~[na:1.8.0_131]
at java.awt.EventQueue.access$500(EventQueue.java:97) ~[na:1.8.0_131]
at java.awt.EventQueue$3.run(EventQueue.java:709) ~[na:1.8.0_131]
at java.awt.EventQueue$3.run(EventQueue.java:703) ~[na:1.8.0_131]
at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_131]
at java.security.ProtectionDomain$JavaSecurityAccessI mpl.doIntersectionPrivilege(ProtectionDomain.java: 80) ~[na:1.8.0_131]
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 726) ~[na:1.8.0_131]
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:201) [na:1.8.0_131]
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:116) [na:1.8.0_131]
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:105) [na:1.8.0_131]
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:101) [na:1.8.0_131]
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:93) [na:1.8.0_131]
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:82) [na:1.8.0_131]


If the menu bar is placed to the MacBook Pro's monitor, this error messages does not appear.

Both DisplayLink Manager App and classic DisplayLink driver has been tried.

I've read a little about this on this forum, but apparently it hasn't been fixed yet.
I'll be glad for any advice or feedback.

Thank you

Had the same problem
 

I had the same problem this morning. In my app, this java code threw a null pointer exception for this line of code.

For some reason, when you have the main monitor set to one that is connected to the dock, getDefualtScreenDevice() returns null.

I was also using java 8.