i bought minecraft java but it only gave me the demo

Hi there!

There are a few resources that may help you fix this problem on https://help.minecraft.net/hc/en-us/articles/360029643892-Can-only-play-Minecraft-demo-Java-Edition-. Make sure that you follow every instruction given on that page. If that still doesn't fix your problem, then I would suggest getting help on the community Discord at https://discord.com/invite/58Sxm23.