Running guam/demo/DEMOAPL1.MLC results in black screen

[jyganci]

Running the guam/demo program DEMOAPL1 from the z390 directory via

bash/asmlg guam/demo/DEMOAPL1 guam

results in a black screen with blue text "DEMOPAPL1 SHOW TN3270 APL CODES" appearing on the second row.

Looking at the guam/demo/DEMOAPL1.MLC source, it should be showing the APL character set using a black color on a green background.

In addition, the texte rendered on the screen with missing parts of some letters. Resizing the window results in the Command and Status literals and corresponding text fields being repositioned incorrectly and lots of extra space can arise.

All screen-related processing is done in z390 src/gz390.java and src/gz390_screen.java. A quick look at src/gz390_screen.java shows that the class extends JPanel but uses the Java paint() method to update its area. JPanel objects should use the Java paintComponent() method to do this. The paint() method was originally used prior to the introduction of Swing.