What is the shortcut in IntelliJ IDEA to find method / functions?

Windows : ^ ctrl + F12

MacOS : ⌘ cmd + F12

Above commands will show the functions/methods in the current class.

Press ⇧ SHIFT TWO times if you want to search both class and method in the whole project.

ctrl + F12 (cmd + F12 on macOS) will show all members of the current class in a popup window and let you pick up one. It works exactly like the ctrl + o shortcut in eclipse, much faster than ctrl + alt + shift + n