Hintergrund meiner Frage sind Dinge wie:Bei einem Privatrechner (mit BlueJ 5.1.0, SAS (neuste Bibliothek) und allen Einstellungsrechten) sieht die Sache so aus:
https://www.bluej.org/versions.html hat gesagt.:Version 5.4.1
Fixed a bug where errors would sometimes not show as red underlines in the editor. The side bar would indicate an error on the line but it was impossible to see the error message.
Version 5.3.0
Fixed a bug which could prevent compiler errors being shown when a stale class file was present
Version 5.2.0
Fixed a bug where errors on the last line of a Java file (often, reached end of file while parsing after a missing close curly bracket) would not show at all.