JCenter maven-metadata.xml doesn't have all module versions from Maven Central

Question

In JCenter net.sourceforge.plantuml:plantuml module doesn't have version 1.2020.15 in maven-metadata.xml .

But, in Maven Central this module has this version listed in maven-metadata.xml .

However, I managed to successfully download net.sourceforge.plantuml:plantuml:1.2020.15 JAR from JCenter . Look like, in this case JCenter redirects me to repo.jfrog.org/artifactory/libs-release-bintray repository, which contains this version. And this artifactory repository also has this version listed in maven-metadata.xml .

JCenter documentations says that it's a mirror of Maven Central. The question is: shouldn't maven-metadata.xml be fully synchronized? It's critical for me, as I use a tool to update my dependencies to latest versions and this tool doesn't update plantuml to the latest version, because this versions isn't listed in maven-metadata.xml in JCenter.

Answer 1

The Synchronisation of packages in Bintray will happen from JCenter to Maven Central. So packages in Maven Central will not always be in JCenter when users request a package that does not exist on JCenter (hence, on-demand), Bintray will try to retrieve it from remote repositories and store it in JCenter.

Therefore, JCenter does not duplicate everything under Maven Central (to be reflected in JCenter). If the package is already linked to JCenter and once the latest version is uploaded to your Bintray account it will be mirrored in JCenter and then you can sync the latest version with Maven Central from your Bintray account.

Please refer the below link for more information on how Maven Central sync works with Bintray: https://www.jfrog.com/confluence/display/BT/Syncing+with+Third-Party+Platforms