How to resolve "Package (...) Cannot be resolved" in Apache Karaf

I am new to Apache Karaf, I migrated from Felix.

I try to run a CDI test but can not resolve the red missing dependencies:

I am pretty sure I must download those red "packages" as bundles from mvnrepository but instead of bundles I only find jar to download.

A bundle is a jar with some additional data in the MANIFEST.MF.

For example, if you look at that jar : https://mvnrepository.com/artifact/javax.enterprise/cdi-api/1.2, you'll notice in META-INF/MANIFEST.MF those lines :

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: 1.7.0_45 (Oracle Corporation)
Built-By: jharting
Build-Jdk: 1.7.0_45
Implementation-Title: CDI APIs
Implementation-URL: http://cdi-spec.org
Implementation-Vendor: JBoss by Red Hat, Inc.
Implementation-Version: 20140411-1123
Specification-Title: CDI APIs
Specification-Vendor: JBoss by Red Hat, Inc.
Specification-Version: 1.2.0
Export-Package: javax.decorator;uses:="javax.enterprise.inject";versio
 n="1.1",javax.enterprise.context;uses:="javax.inject";version="1.1",j
 avax.enterprise.inject.spi;uses:="javax.enterprise.context.spi,javax.
 el,javax.enterprise.inject,javax.interceptor,javax.enterprise.event";
 version="1.1",javax.enterprise.util;version="1.1",javax.enterprise.ev
 ent;uses:="javax.enterprise.util";version="1.1",javax.enterprise.inje
 ct;uses:="javax.inject,javax.enterprise.util,javax.enterprise.context
 ";version="1.1",javax.enterprise.context.spi;version="1.1"
Tool: Bnd-0.0.357
Bundle-Name: CDI APIs
Bundle-Vendor: JBoss by Red Hat, Inc.
Bundle-Version: 1.2.0
Bnd-LastModified: 1397208243348
Bundle-ManifestVersion: 2
Bundle-Description: APIs for CDI (Contexts and Dependency Injection fo
 r Java EE)
Bundle-License: http://www.apache.org/licenses/LICENSE-2.0.html
Import-Package: javax.decorator;version="1.1",javax.el;version="2.2",j
 avax.enterprise.context;version="1.1",javax.enterprise.context.spi;ve
 rsion="1.1",javax.enterprise.event;version="1.1",javax.enterprise.inj
 ect;version="1.1",javax.enterprise.inject.spi;version="1.1",javax.ent
 erprise.util;version="1.1",javax.inject,javax.interceptor;version="1.2"
Bundle-SymbolicName: javax.enterprise.cdi-api
Bundle-DocURL: http://jboss.org

Name: Build-Information
Maven-Version: 3.1.0
Build-Time: 20140411-1123
Os-Name: Linux
Java-Version: 1.7.0_45
Java-Vendor: Oracle Corporation
Os-Version: 3.7.3-101.fc17.x86_64
Os-Arch: amd64
SCM: 5a0981caa28053c49f9e1932ba1f629a51e355c2

Bundle-* are the ones that interest you. For example, Export-Package contains javax.enterprise.context;uses:=...;version="1.1" which indicates that this bundle will export the package javax.enterprise.context.

So installing that bundle, will automatically provide to your other bundles the ability to Import-Package that package.

Note that if there wasn't any Export-Package, I know karaf can try to "wrap" your jar into a bundle. However, it can leads to non really optimal bundles. When you want a particular package but the official one is not osgi-friendly, you can check the servicemix organization, if any has been created specifically : https://mvnrepository.com/artifact/org.apache.servicemix.

In your specific case, a bundle install -s mvn:javax.enterprise/cdi-api/1.2 (or dropping the jar in the deploy folder) should do the trick.

I highly encourage you to read the three OSGI layers (modularity, lifecycle & services) to better understand what karaf is doing behind the scene. For example this book, but you can surely find good informations on the internet too : https://www.manning.com/books/osgi-in-action