Intellij - Errors JAVA (imports, etc...) doesn't detect

Question

I'm starting use the IntelliJ-IDEA, but my java files doesn't detect errors like imports for example. I don't create one project java, because i'm using different languages in same project, but I want that in the java files, he detect the errors. How can I make this?

Answer 1

Intellij can work very well standard project layouts. If yours is not standard - tell Intellij how it is structured: from open workspace, select File -> Project Structure (Ctrl+Alt+Shift+S), and go through all the tabs to setup specifics:

The most important tabs are probably:

1. Project tab, where you specify jdk to use with the project (JAVA_HOME if you will)
2. Modules -> Sources where you tell intellij which directories should be treated as java packages
3. Modules -> Paths to setup where you want to put compiled classes
4. Modules -> Libraries - to specify any additional jars to be used.

Assume you have two java files in your project:

package com.myproject // this one have package

public class SomeClass{
    //whatever
}

and

public class Main {
    // whatever - no package
}

so you should have them inside some directory:

directory
  |- com
  |  |- mypackage
  |     |- SomeClass.java
  |- Main.java

In such structure - the directory is sources root. Mark it as such