IntelliJ IDEA Notes

Cannot resolve symbol

Choose File → Invalidate Caches / Restart to clear caches and rebuild indexes. This can take a while. If it does not help, find IntelliJ’s cache directory, delete it, and try again.

I encountered a bug after updating Maven’s settings.xml. A simplified pom.xml looked like:

<build>
    <filters>
        <filter>src/main/filters/filter-${env}.properties</filter>
    </filters>
</build>
<profiles>
    <profile>
        <id>dev</id>
        <properties>
            <env>dev</env>
            <doc-enable>true</doc-enable>
        </properties>
    </profile>
</profiles>

IntelliJ reported that env could not be resolved, even though the project compiled and ran. Moving profiles before build removed the error; moving it back did not restore the error. I could reproduce it after updating settings.xml and reimporting dependencies.

IntelliJ IDEA 2016.3.4, build IU-163.12024.16

Note: Maven Helper may have caused this behavior.

Lombok annotations such as @Getter are not recognized

Open Preferences, search for annotation, and enable annotation processing as shown:

Convert another project into a Maven project

Add the appropriate framework support when opening the project, or right-click the project and choose Add Framework Support.

Optimize and remove unused imports

Press Command+Option+O.

Generate serialVersionUID

Place the cursor on the class name, press Option+Enter, and choose the corresponding action.

Originally published on SegmentFault.