Not launching in Mac OS Mojave 10.14

[massisenergy]

When java jflowsim.Program is run in terminal, it goes into Java but then it halts without opening any window. The following error appears in terminal:

javax.swing.UnsupportedLookAndFeelException: [The Microsoft Windows Look and Feel - com.sun.java.swing.plaf.windows.WindowsLookAndFeel] not supported on this platform
at java.desktop/javax.swing.UIManager.setLookAndFeel(UIManager.java:574)
at java.desktop/javax.swing.UIManager.setLookAndFeel(UIManager.java:632)
at jflowsim.view.MainWindow.(MainWindow.java:60)
at jflowsim.Program.main(Program.java:25)
Exception in thread "main" java.lang.NullPointerException
at java.desktop/javax.swing.ImageIcon.(ImageIcon.java:217)
at jflowsim.view.img.ImageUtilities.createImageIcon(ImageUtilities.java:28)
at jflowsim.view.configdialog.ConfigDialog.(ConfigDialog.java:30)
at jflowsim.view.MainWindow.(MainWindow.java:70)
at jflowsim.Program.main(Program.java:25)

[biels]

It looks like the images are not included in the repo:

This folder should come along with it

[crohr88]

That folder appears to be in the correct location and in the repo?

[crohr88]

I was having the same issue on Windows. The resources could never be found and there was a method trying to get them that always returned null, preventing the GUI from loading.

The problem was that the classpath needs to be set to the src folder explicitly on compilation. Only this exact combination worked, trying to compile in any other way would appear successful but then error when running.

cd to the src folder, then
javac -cp . ./jflowsim/Program.java
You should now be able to successfully launch the program with the following:
java jflowsim.Program

Thank you to Vladimir B. on upwork who helped me figure this out.