title: Java project folder structure in IntelliJ IDEA
body: <p>What is an acceptable folder structure for Java projects in IntelliJ IDEA?</p>
  
  <p>Multiple sources (<a href="https://stackoverflow.com/a/28161314/4490400">like this</a>) suggest the following structure:</p>
  
  <pre><code>.
  │ .idea    
  └── src
      ├── main
      │   ├── java   
      │   │   └── com.simpleproject
      │   │       └── SimpleClass.java
      │   └── resources
      └── test
          ├── java
          │   └── com.simpleproject
          │       └── SimpleClassTest.java
          └── resources
  </code></pre>
  
  <p>I know this has worked before, but right now it is complaining <code>java.lang.SecurityException: Prohibited package name: java</code></p>
  
  <p><a href="https://stackoverflow.com/questions/5490555/prohibited-package-name-java">Apparently</a>, <code>java</code> is not allowed as a package name. I don't understand why it's sometimes acceptable and sometimes not acceptable. Can someone provide a complete example of an acceptable project folder structure in a Java project in IntelliJ IDEA?</p>