I'm using OSX Yosemite and I hate how windows maximization works... previously (with Mountain Lion) I was using RightZoom, in order to always maximize windows as it should be (using the whole space). I discovered that by clicking on the green button with ALT + SHIFT the maximization is applied as I like, BUT is very annoying... so I created a shortcut (CMD+SHIFT+M) by going to preferences > shortcuts > app shortcuts > clicking on "+" and creating a shortcut named "Zoom"... it works great for all the applications but not for the Java ones (or at least it does not work for Intellij Idea and PyCharm)... so... are app shortcuts available only for native Cocoa applications? Is there another way for a fast and simple maximization? (I was thinking about some kind of "defaults write blahblah", but I didn't find anything)
It's not strictly speaking about Cocoa apps vs Java apps.
What you're doing when you create a shortcut like that is assigning a keyboard shortcut to existing menu items. So if the application has a "Zoom" menu item, your keyboard shortcut will activate it.
If you have a window open that doesn't have a Zoom menu item, or where the Zoom menu item is disabled, your shortcut won't work.
Your shortcut will work in Eclipse for example, even though it's a Java application, because it provides the Zoom action.
So there won't be a system-wide way to assign a shortcut to this action without using third-party software - either the application provides the Zoom action or it doesn't. It might be worth filing feature requests with the application developers, as it's standard in OS X applications to provide this menu item.
http://spectacleapp.com is a free app which will allow you to do all sorts of window manipulation on the Mac, including “Fullscreen” which really means “maximize”:
You can set your own keyboard shortcuts, of course.