Unable to run Java code with Intellij IDEA

Question

I have just downloaded the IDE, and I want to edit my first Java file with it, I'm not interested in creating a whole project, just editing the single file.

So I opened the file from my desktop with Intellij IDEA as I set it as my default program for opening .java files.

I write some code and the main run and debug buttons are greyed out! I can't run my code!

I have already installed Java 8 update 45 64-bit (I have a 64 bit OS) as well as the Java development kit (J8U45). I have set my global IDE SDK as my JDK installation, and when it prompts me I also set this as my project SDK, but still the run and debug buttons are unable to be used!

Edit: I am also unable to run my file regardless of if its in a project or not.

Edit 2: Screenshot of my project setup

Answer 1

Move your code inside of the src folder. Once it's there, it'll be compiled on-the-fly every time it's saved.

IntelliJ only recognizes files in specific locations as part of the project - namely, anything inside of a blue folder is specifically considered to be source code.

Also - while I can't see all of your source code - be sure that it's proper Java syntax, with a class declared the same as the file and that it has a main method (specifically public static void main(String[] args)). IntelliJ won't run code without a main method (rather, it can't - neither it nor Java would know where to start).