Consider all the improvements to the above software that came after Oracle's purchase of Sun. There was a boatload of them and they keep coming. Oracle is paying for that.
They are all free, and that is because of Oracle, not because of Sun as Sun does not exist anymore.
Improvements? How much? They ruined OpenOffice, triggering the LibreOffice fork. They ruined MySQL, triggering the MariaDB fork. The original Sun would have done 10X better improving those things they made.
They were project from Sun Microsystems originally, but Sun Microsystems doesn't exist anymore. Oracle have chosen to keep some of the Sun products open/free (they've closed support for others, such as OpenSolaris, which was continued through an open-source fork).