I have some trouble with continue using GanttProject because of the license changes of Oracle regarding Java. I am not allowed to use an unlicensed version of a software at my institution, also I am not allowed to use old not updated versions of a software, because of internet security (virus, spam, etc.). Consequently using Java from Oracle is no option for me anymore. Instead I installed an open Java version AdoptOpenJDK (https://adoptopenjdk.net/). Nevertheless when I start GanttProject it keeps asking me to install the newest Java version before launching.
It would be supper helpful to get some advise to make GanttProject work with some kind of Open-Java software. I really would like to go on using GanttProject.
Looking forward to some recommendations.