OT: Maven and Gradle are both build systems which are able to download declared build, test and runtime dependencies, compile and package everything, run unit and integration tests and distribute the package afterwards.
Both prefer convention over configuration (sources are expected to stay beneath src/main/java, test sources beneath src/test/java or src/test/groovy) and are easily expandable by plugins which e.g. provide support for css compilation, groovy or kotlin support, creation of rpms or debs etc. Gradle allows more twiddling being a groovy based DSL, which is good and bad at the same time, Maven pushes you into the direction of (often reusable) plugin creation and is IMO better fitted for enterprises.
Back to topic: both use the same big repository for dependencies and probably the Jax libraries may just be declared as dependencies.