I get support from Redhat on their commercial enterprise class systems. Their support is phenomenal and their consultants are among the smartest people I have ever seen. Without support, yeah, it could be an issue. Still, I am a very happy customer of Red Hat. I guess I could go without paying, but you get what you pay for. I'm not happy with Vista for trading, though. They mucked around with their scheduler and certain situations cause issues for me, so I ported time-critical stuff off Vista and use it strictly for rendering data and reporting system.
What a load of old nonsense. It depends which open source software or which closed source software you a talking about. If you run one of the major Linux distributions, there are frequent software updates available. Not just for the operating system itself, but also for the 10,000+ software packages in the repository. And it's all in one place - a one stop shop - with a package management system that works pretty well. And you can choose which upgrades/patches/fixes you want to install - all, none or anywhere in between. Software fixes are far more timely than those delivered by MS. If you are directing the comment at Java, it is nonsensical. The Java JVM release/upgrades/fixes are managed by Sun and much if not most of the work ius done by Sun employees. As the previous poster indicated, commercial support is available for several Linux distributions if you wish to pay. Finally it should be pointed out that huge parts of the internet are powered by open source software as are many mission critical systems.
Java won't "damage your computer", and Java related viruses or other security issues are extremely rare (to the point of being non-existant). How much memory have you got in your PC ? These days you should consider 2 Gbyte to be the minimum. Memory is very cheap.
I installed java 11 over 10 on release. No problems with TWS or anything else. What's the application you're getting a warning about - maybe they need to fix something?