So today our informatics showed us how to download a file from the internet using Firefox.
It was BlueJ...
So he told us the people who develop BlueJ randomly include the JDK in BlueJ or don't.
He told us it's a bit like Russian roulette whether JDK will be included or not.
What he didn't know,
the standalone version for Windows obviously included it (.exe... ) and the version for other systems doesn't include the JDK.....