Question: I'm learning to use Eclipse for Java programming, it's my first experience with an IDE. I've been coding for quite a while, working slowly through the MOOC java course from The University of Helsinki (iirc) and am just starting the actual Object-Oriented Programming section. 

So far I've been saving each new problem as a class in the project: "MOOC week X", however I suspect that this isn't the correct way to do this. What is the correct/industry standard way to save java files with respect to projects, source files, packages and classes?

Answer: 
Methods, classes, packages (on the language level) and projects (on the IDE level) are just ways to organize code.

This organization is also called design. Its your responsibility as programmer to take care of the design.

I would recommend to not judge a design in terms of right or wrong, but rather in terms of useful or not useful.

* There is nothing wrong with creating a separate project for every week of your MOOC.
* You could also have one project and create a separate package for every week (if allowed by the MOOC tasks).

You need to develop a sense what is useful. One important aspect of that is *complexity*: On all design levels you can ask that question: Is this construct (class, package, project) getting to *crowded* or *complex*? Then a reorganisation might be useful: Split the class, the package, the project.

The good news is that you don't have to get it right in the beginning. Once you feel that a complexity limit is reached, reorganize your code base.
Usually you have a *src* (for maven projects it's *src/main/java*) directory in your project directory in which you create packages (*talorias.stackoverflow* is the package name ehe). 

[![Eclipse: Package Explorer](https://i.stack.imgur.com/Dyk4Q.jpg)](https://i.stack.imgur.com/Dyk4Q.jpg)

In Eclipse you just right-click the *src* folder to do so. Eclipse then automatically creates the sub-directories for you. 

```
\StackOverflow>tree /f /a

|   .classpath
|   .project
|
+---.settings
|       org.eclipse.jdt.core.prefs
|
+---bin
\---src
    \---talorias
        \---stackoverflow
                StackOverflow.java

```

Happy hacking! ;)