Minecraft CurseForge

Hey i have a problem:

i would really really love to play some modded Minecraft, especially the rlcraft modpack. Im on Mac (high sierra right now) and i downloaded the twitch desktop app, installed Minecraft on there and everything else, also java, but:

1. the twitch app doesn't recognize that i already installed java in the Settings>Minecraft>Java Settings, it rather tells me "Java was not found on your system. Please install Java and refresh".

and 2. every time i press play on a modpack, the game launcher starts (via java btw) and gives me this error after pressing play again there:

Java HotSpot(TM) 64-Bit Server VM warning: Ignoring option PermSize; support was removed in 8.0Java HotSpot(TM) 64-Bit Server VM warning: Ignoring option PermSize; support was removed in 8.0Exception in thread "main" java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap') at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34) at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

with my (really limited) knowledge i tried everything to deinstall everything java-related i found and reinstalled it via the link given to me by twitch, i even tried to download different versions of java via different sources... nothing makes a difference! Please somebody help!

I also tried out different changes to the JVM Arguments, but no progress there ether...

This problem was already kinda addressed in this post, but even though it seems to work for others this does not work for me at all (and hammy0013).

So please, if somebody has any idea what i should do or has any questions, please tell me!

Huge Thanks to anyone who reads this and tries to help! :)

In reply to itzgrigon:

 You need to install a different version of java.

In reply to jtrent238:

 so what version is needed

In reply to FallenSurviverX:

 https://java.com/en/download/manual.jsp

In reply to FallenSurviverX:

 Did updating it fix the problem for you? I'm still getting the same issue with twitch not recognizing Java

In reply to Blizburger99:

 What version of java are you using?

In reply to jtrent238:

 i installed this version and this and it keeps saying 

In reply to nicotine_sandwich:

 java is installed because it is running, but Twitch is not recognizing it.

You could try to use this launcher that I have found. https://gdevs.io/

Java HotSpot(TM) 64-Bit Server VM warning:

I have the exact same problem, also running Mac (High Sierra as well) with the exact same errors and issues. Just downloaded the latest version of java, yet nothing seems to help. Is Twitch just broken?

In reply to Blizburger99:

 it will not work for me 

Edit 2: So I just found the solution (at least for this situation,) I reinstalled the twitch launcher and it started working again and all of my downloaded modpacks remained intact as well as all of the saves on them.

I'm experiencing a very similar issue with the Twitch launcher, but first some backstory for what lead up to this: I was playing a modpack from the twitch launcher and went afk to deal with something IRL, I had the game on the escape menu to keep it paused. Partway through my task, the power went out.

Now, when I press play on any of my modpacks in the launcher it gives me the message "Java must be installed to launch Minecraft with the current launch method."

Edit: after I turned my computer back on I checked java and updated it