How to Fix IntelliJ Import Errors — Missing Classes and Packages

In this tutorial, you'll learn about How to Fix IntelliJ Import Errors. We cover key concepts, practical examples, and best practices.

The Problem

IntelliJ cannot resolve a class or package:

import com.example.MyClass;  // Cannot resolve symbol 'MyClass'

Quick Fix

Step 1: Invalidate caches

File > Invalidate Caches and Restart > Invalidate and Restart

This clears the internal index and rebuilds from scratch.

Step 2: Reload the project

File > Reload All from Disk

Or rebuild the project:

Build > Rebuild Project

Step 3: Check module dependencies

File > Project Structure > Modules > Dependencies tab

Ensure the required library or module is added. Click + to add a dependency.

Step 4: Reimport Maven/Gradle dependencies

For Maven:

View > Tool Windows > Maven > Reload All Projects

For Gradle:

View > Tool Windows > Gradle > Reload All Gradle Projects

Step 5: Set the correct SDK

File > Project Structure > Project > Project SDK

Ensure the correct Java/ADK/Go SDK is selected.

Step 6: Check the module source root

Right-click the source folder > Mark Directory as > Sources Root.

Prevention

• Let Maven/Gradle sync complete before coding.
• Use Ctrl+Shift+A and type "Reload" for quick access.
• Keep the .idea/ directory in version control for team consistency.

Common Mistakes with import error

1. Forgetting that lazy evaluation defers computation until the value is forced, causing space leaks with unevaluated thunks
2. Using return to exit a function early instead of wrapping a pure value in the monad
3. Mixing let bindings with <- bindings in do notation, producing type errors

These mistakes appear frequently in real-world INTELLIJ code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ