Spring Boot builds OK, but Heroku deploy fails

Question

I've looked this up extensively and found no useful answer. I'm trying to deploy this API with Heroku. It's a pre-existing GitHub repository, I followed Heroku's devcenter guidelines. I tried to deploy via Git and the Heroku Maven Plugin, and the result is the same: I can build it locally and everything is fine, but when I cd to ~/workspace/API/myapi/ and try to push it to Heroku doing git push heroku main:main I get:

Enumerating objects: 237, done.
Counting objects: 100% (237/237), done.
Delta compression using up to 4 threads
Compressing objects: 100% (179/179), done.
Writing objects: 100% (237/237), 91.06 KiB | 4.14 MiB/s, done.
Total 237 (delta 61), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote: 
remote: -----> Java app detected
remote: -----> Installing JDK 11... done
remote: -----> Executing Maven
remote:        $ ./mvnw -DskipTests clean dependency:list install
remote: ./mvnw: 219: ./mvnw: cannot open /tmp/build_f4dfb6d1/API/myapi/.mvn/wrapper/maven-wrapper.properties: No such file
remote: /tmp/build_f4dfb6d1/API/myapi/.mvn/wrapper/maven-wrapper.jar: No such file or directory
remote: Error: Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain
remote: Caused by: java.lang.ClassNotFoundException: org.apache.maven.wrapper.MavenWrapperMain
remote: 
remote:  !     ERROR: Failed to build app with Maven
remote:        We're sorry this build is failing! If you can't find the issue in application code,
remote:        please submit a ticket so we can help: https://help.heroku.com/
remote: 
remote:  !     Push rejected, failed to compile Java app.
remote: 
remote:  !     Push failed
remote: Verifying deploy...
remote: 
remote: !       Push rejected to myapiheroku.
remote: 
To https://git.heroku.com/cashonlineheroku.git
 ! [remote rejected] main -> main (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/myapiheroku.git'

• /home/myuser/workspace/API/myapi/.mvn/wrapper/ contains the files maven-wrapper.jar , maven-wrapper.properties and MavenWrapperDownloader.java .
• /home/myuser/workspace/API/myapi/system.properties specifies
  java.runtime.version=11 .
• /home/myuser/.m2/repository/ar/com/api/myapi/ contains
  myapi.0.0.1-SNAPSHOT.jar .
• You can find pom.xml , application.properties , etc in the repository linked above.

What am I missing? Let me know if you need additional information. Thanks in advance!

Answer 1

It looks like you have a mvnw file in the root of your project directory but are missing other files required by Maven wrapper. Those usually reside in the .mvn/wrapper directory of your application. You might have deleted them.

You have two options:

1. Delete the other files for Maven Wrapper as well: mvnw and mvnw.cmd
2. Reinstall the missing files for Maven Wrapper: mvn -N io.takari:maven:0.7.7:wrapper

I'd go for option 2. Using the wrapper is generally preferred to ensure your project is run with the Maven version you expect.