What exactly are Maven and Gradle and Ant? I'm learning Java in school right now and nowhere in class or in my textbook have they ever been mentioned, but every time I'm asked to code a project of course I have to pick whether I use Java with Maven, Java with Gradle, or Java with Ant. I always just pick Java with Maven because I have no idea what I'm actually doing, but it would be nice to know what I'm picking and why. I googled it but just found a bunch of articles that assume you already know what they are and want to know the differences between the 3. I read a few of those articles and now I'm even more confused, they talked about how they are good for different things because they are different languages with different dependencies.
But... isn't Java the language? So can someone explain what exactly Maven and Gradle and Ant are and why I need to pick which one I want to use when I'm coding in Java?
Edit: also, how do I know which one to pick, and when it matters what to pick?