Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain

[hsluoyz]

I have a spring boot project here: https://github.com/jcasbin/jcasbin-springboot-plugin. I encountered the following error in Travis CI:

3.43s$ ./mvnw install -DskipTests=true -Dmaven.javadoc.skip=true -B -V
/home/travis/build/jcasbin/jcasbin-springboot-plugin
Picked up _JAVA_OPTIONS: -Xmx2048m -Xms512m
Error: Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain
The command "eval ./mvnw install -DskipTests=true -Dmaven.javadoc.skip=true -B -V " failed. Retrying, 2 of 3.

It seems that the mvnw command fails. This file is generated by my IDE: IntelliJ IDEA 2018.1. I don't know what it is used for and why is fails?

[wilkinsona]

That's a problem with Maven's wrapper and doesn't have anything to do with Spring Boot. It looks like the .mvn directory that contains the wrapper's jar is missing from your repository. If you need some further help with setting up the wrapper correctly, please ask a question on Stack Overflow.

[hsluoyz]

Thanks. I just posted a question at: https://stackoverflow.com/questions/50104172/could-not-find-or-load-main-class-org-apache-maven-wrapper-mavenwrappermain