How to make IntelliJ IDEA recognize build-time generated sources?

Question

I made a small zip example to illustrate the issue.

I have in the project the Animal class from AutoValue example and a maven pom file to do the code generation and compilation. See below.

Running mvn clean install works great and generates and compiles everything into target/classes:

The problem is that IntelliJ doesn't recognize AutoValue_Animal:

So how to make IntelliJ IDEA recognize build-time generated sources?

* Preferably, without needing to change IDEA specific setting, in order to keep the dev env consolidated around Maven.

Class:

package kilaka;

import com.google.auto.value.AutoValue;

@AutoValue
public abstract class Animal {
    static Animal create(String name, int numberOfLegs) {
        // See "How do I...?" below for nested classes.
        return new AutoValue_Animal(name, numberOfLegs);
    }

    abstract String name();

    abstract int numberOfLegs();
}

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>kilaka</groupId>
    <artifactId>auto-test</artifactId>
    <version>1.0.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>com.google.auto.value</groupId>
            <artifactId>auto-value</artifactId>
            <version>1.2</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</project>

Answer 1

Found a solution that worked for me but don't like it. I unmarked the target folder from Excluded and marked the classes as Sources.

In order to continue excluding all other target folders, I had to mark all other folders as excluded.

This is a bad solution because:

1. If you want to keep your code clean from dev-env, you aren't committing IDEA'a configuration files. Thus need to repeat this step on every clone.
2. If additional folders are starting to get into the target folder, you need to manually exclude them.
3. The solution is not maven centric, causing dev-env configuration to be split into several files.

Answer 2

It seems that the following fixes the issue:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.5</version>
    <configuration>
        <source>6</source>
        <target>6</target>
    </configuration>
</plugin>

This caused the file AutoValue_Animal.java to be generated in target/generated-sources/annotations, which IntelliJ IDEA read without any additional tweaking.

I read that annotation processing wasn't supported in Java 5 (yet the class was generated). See more info here.