can not lunch minecraft 1.8 pre 3

Dupe of MCL-1893 / MC-65836

Try re-installing your java and make sure that you verify it when it finishes this happened to me and it fixed it. If that does not fix it then go to %appdata% delete your .minecraft folder and repeat the java installation and verify then run minecraft. Hope this helps 🙂

happened to me again in version 1.12.2 and none of the above helped

Same as Petr, I'm using fedora 26
Everything was fine yesterday.
I tried downgrading java to previous version (from java-1.8.0-openjdk.x86_64 1:1.8.0.144-7.b01.fc26 to java-1.8.0-openjdk.x86_64 1:1.8.0.131-7.b12.fc26), removing my .java and .minecraft folder and re-downloading Minecraft without success, still stuck on the same error message "Error: Could not find or load main class net.minecraft.client.main.Main"
Using launcher 1.6.82-j and Minecraft 1.12.2

Exactly identical to @thraxer except I'm on Fedora 21. All versions, reinstall steps, etc. were the same. Also tried running the launcher as sudo, same failed result. SELinux is `setenforce 0`, nothing shows in any logs anywhere except in the launcher dialog.

I am also having this problem on ubuntu 16.04 and 17.10, with both oracle jdk and openjdk.

I'm having the same problem. As this post.

Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release
Error: Could not find or load main class net.minecraft.launchwrapper.Launch

Just in case, here's a link to the most recent post on this issue https://bugs.mojang.com/browse/MC-121292