<Swing Dev> [12] RFR JDK-8211703: JInternalFrame : java.lang.AssertionError: cannot find the internal frame

[Prasanta Sadhukhan]

Hi All,

Please review a cleanup of the code where wrong assertion is used when 
Component is an instance of BasicInternalFrameTitlePane.

Now, BasicInternalFrameTitlePane is extended from JComponent and not 
from JInternalFrame
so it will never satisfy the if-else condition if "Component is 
instanceof BasicInternalFrameTitlePane",
so proposed fix is to assert only if the component is not an instance of 
BasicInternalFrameTitlePane

diff -r d96a607e9594 
src/java.desktop/share/classes/com/sun/java/swing/plaf/gtk/Metacity.java
--- 
a/src/java.desktop/share/classes/com/sun/java/swing/plaf/gtk/Metacity.java 
Tue Sep 18 18:32:03 2018 -0700
+++ 
b/src/java.desktop/share/classes/com/sun/java/swing/plaf/gtk/Metacity.java 
Thu Oct 04 19:53:10 2018 +0530
@@ -337,7 +337,9 @@
          } else if (comp instanceof JInternalFrame.JDesktopIcon) {
              return ((JInternalFrame.JDesktopIcon)comp).getInternalFrame();
          }
-        assert false : "cannot find the internal frame";
+       if (!(comp instanceof BasicInternalFrameTitlePane)) {
+            assert false : "cannot find the internal frame";
+       }
          return null;
      }

Regards
Prasanta