code: @Nullable
      public String getUrl() {
          if (getRepositoryUrl() == null)
              return null;
          return getRepositoryUrl() + "/" + getGroupId().replace('.', '/') + "/" + getArtifactId() + "/" + getVersion() + "/" + getFileNameWithBaseVersion();
      }
docs: URL of the artifact on the maven repository on which it has been deployed if it has been deployed.
  
  @return URL of the artifact or {@code null} if the artifact has not been deployed (if "{@code mvn deploy}" was not invoked)