Download Maven artifacts

WanakuMavenDownloader resolves Maven artifacts and their transitive dependencies at runtime, and makes them available through a class loader. Use it to add libraries that a route or a plugin needs, without a rebuild.

Prerequisites

The capabilities-maven-downloader module. See Get started.
Network access to Maven Central or to your repositories.

Download artifacts

java

try (WanakuMavenDownloader downloader = new WanakuMavenDownloader()) {
    List<Path> jars = downloader.download(List.of(
            GAV.parse("org.apache.camel:camel-jackson:4.22.0")));
    downloader.applyToCurrentThread();
    // Classes from camel-jackson and its dependencies are now loadable.
}

download resolves all given artifacts as one graph, with Maven conflict mediation. It returns the paths of all resolved JAR files, transitive dependencies included. If an artifact cannot be resolved, it throws a DependencyDownloadException.

After the download:

getClassLoader() returns a class loader with all downloaded artifacts.
applyToCurrentThread() sets that class loader as the context class loader of the current thread.
close() releases the class loader. Use try-with-resources, or call close() when you no longer need the classes.

Select repositories and the cache

Constructor	Remote repositories	Local repository
`WanakuMavenDownloader()`	Maven Central	`~/.m2/repository`
`WanakuMavenDownloader(List<Repository>)`	Maven Central and the given repositories	`~/.m2/repository`
`WanakuMavenDownloader(List<Repository>, Path)`	Maven Central and the given repositories	The given path
`WanakuMavenDownloader(List<Repository>, Path, ClassLoader)`	Maven Central and the given repositories	The given path

Use the constructor with a ClassLoader argument to set the parent of the new class loader. WanakuMavenDownloader(ClassLoader) does the same with the default repositories and cache.

A Repository has an id and a url:

java

new Repository("company", "https://repo.example.com/maven2")

Write coordinates

GAV.parse("groupId:artifactId:version") reads a coordinate. It throws IllegalArgumentException if the text does not have three parts.

GAV.parse("groupId:artifactId", properties) gets the version from a Properties object. It looks for the key groupId:artifactId first, then for the key groupId.

Next steps

Load service catalogs and routes: get the dependency files of a route.
Modules: the other SDK modules.

Download Maven artifacts ​

Prerequisites ​

Download artifacts ​

Select repositories and the cache ​