java.lang.ClassNotFoundException: jakarta.servlet.http.HttpServlet

Q: Update imports from javax to jakarta

When to use: Use this when migrating an existing app to Spring Boot 3.. Spring Boot 3 migrated from Java EE (javax.*) to Jakarta EE (jakarta.*). You must update all imports in your Java files.

Q: Upgrade third-party dependencies

When to use: Use this if your code is correct, but a library you are using still relies on javax.. Libraries like SpringDoc OpenAPI, Lombok, or older Swagger versions must be upgraded to versions that support Spring Boot 3 and Jakarta EE.

Q: Ensure Java 17+ is being used

When to use: Use this if your build fails with package does not exist errors.. Spring Boot 3 requires a minimum of Java 17. Ensure your pom.xml and IDE are configured to use Java 17 or 21.

🔴 The Error You're Seeing

Confirm this matches your console output. If it does, you're in the right place.

ERROR LOG

2026-02-14 19:15:20.000 ERROR 8842 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: java.lang.NoClassDefFoundError: jakarta/servlet/http/HttpServlet
Caused by: java.lang.ClassNotFoundException: jakarta.servlet.http.HttpServlet

⚡ Quick Fix Works 80% of the time

Change all javax.servlet.* imports to jakarta.servlet.* in your Java code.

// Change this:
// import javax.servlet.http.HttpServletRequest;

// To this:
import jakarta.servlet.http.HttpServletRequest;

🧠 Why this Happens

Tap to expand the deep technical explanation

Spring Boot 3.x uses the Jakarta EE 9+ namespaces instead of the old Java EE javax namespaces. The JVM is trying to load a class using the new jakarta path, but it cannot find it because either your code or a dependency is still providing the old javax classes.

The HITEC City Parking Spot Analogy:

It is like trying to use a key from an old house (javax) on the door of a newly built house (jakarta). The shape is slightly different, so the lock (Spring Boot 3) rejects it.

🔁 How to Reproduce Confirm this is your error

Use a Spring Boot 2.x-era dependency that imports javax.servlet.* classes in a Spring Boot 3 application, then start the app. You get ClassNotFoundException: jakarta.servlet.http.HttpServlet.

🛠️ Solutions (3 Ways to Fix)

Solution 1✓ Most common cause

Update imports from javax to jakarta

👉 Use this when migrating an existing app to Spring Boot 3.

Spring Boot 3 migrated from Java EE (javax.*) to Jakarta EE (jakarta.*). You must update all imports in your Java files.

// Old (Spring Boot 2.x)
import javax.persistence.Entity;
import javax.validation.constraints.NotNull;

// New (Spring Boot 3.x)
import jakarta.persistence.Entity;
import jakarta.validation.constraints.NotNull;

Solution 2

Upgrade third-party dependencies

👉 Use this if your code is correct, but a library you are using still relies on javax.

Libraries like SpringDoc OpenAPI, Lombok, or older Swagger versions must be upgraded to versions that support Spring Boot 3 and Jakarta EE.

<!-- Upgrade SpringDoc for Spring Boot 3 -->
<dependency>
    <groupId>org.springdoc</groupId>
    <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
    <version>2.1.0</version>
</dependency>

Solution 3

Ensure Java 17+ is being used

👉 Use this if your build fails with package does not exist errors.

Spring Boot 3 requires a minimum of Java 17. Ensure your pom.xml and IDE are configured to use Java 17 or 21.

<properties>
    <java.version>17</java.version>
</properties>

📋 Version Notes

Spring Boot 2.x

Uses javax.servlet, javax.persistence, etc.

Spring Boot 3.x

Completely removed javax. Uses jakarta.servlet, jakarta.persistence, etc.

🛡️ How to Prevent This Next Time

When upgrading to Spring Boot 3, use the OpenRewrite migration tool to automatically handle javax to jakarta package replacements.