In one sentence, describe what the following article is about:

You will need Java installed in order to run Minecraft on OS X. You can download Java for OS X 10.10 (Yosemite) by clicking here. Mojang is working on a Mac installer that doesn't require Java anymore, but it is not yet available. You can find it at minecraft.net/download. This can be found under the "Minecraft for Windows" section. Minecraft.dmg link. This will download the installer for the Mac version of Minecraft. You can find it in your Downloads folder. This will install Minecraft. This is error occurs because OS X is set to not allow programs that were downloaded from places other than the App Store.  Click the Apple menu and select "System Preferences". Select the "Security & Privacy" option. Select "Anywhere" from the "Allow applications downloaded from" section.

Summary:
Download and install Java. Visit the Minecraft Download page. Click the "Show all platforms" link. Click the . Double-click the downloaded DMG file. Drag the Minecraft program into your Applications folder. I get an error saying Minecraft is damaged when trying to run it.