code: protected String resolveArtifactId() {
  		if (this.artifactId != null) {
  			return this.artifactId;
  		}
  		if (this.output != null) {
  			int i = this.output.lastIndexOf('.');
  			return (i != -1) ? this.output.substring(0, i) : this.output;
  		}
  		return null;
  	}
docs: Resolve the artifactId to use or {@code null} if it should not be customized.
  @return the artifactId