Unable to install jar to local maven repo

I am trying to use the project which uses this gradle config: https://github.com/treelogic-swe/aws-mock/blob/master/build.gradle but I am having trouble installing the jar into my local maven repo via gradle install. It complains about multiple artifacts. Not sure what the issue is besides it getting confused by the war and jar.

$ gradle install :compileJava UP-TO-DATE :processResources UP-TO-DATE :classes UP-TO-DATE :jar UP-TO-DATE :javadoc UP-TO-DATE :javadocJar UP-TO-DATE :sourcesJar UP-TO-DATE :war UP-TO-DATE :install FAILED

FAILURE: Build failed with an exception.

  • What went wrong: Execution failed for task ‘:install’. > Could not publish configuration ‘archives’

A POM can not have multiple main artifacts. Already have MavenArtifact aws-mock:war:war:null, trying to add MavenArtifact aws-mock:jar:jar:null

  • Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 5.446 secs

The published POM has to be of either type ‘jar’ or type ‘war’ so you’ll have to give your jar artifact a classifier to uniquely identify it.