I am stuck in getting the apache karaf rest example to work.
I successfully managed to install karaf on my laptop and get a hello world example application on the console to run. I also managed to compile the example applications in the C:\karaf\examples using mvn install.
As a next step I tried to "install" the rest-example as discussed in the README.md by executing the command
feature:repo-add mvn:org.apache.karaf.examples/karaf-rest-example-features/4.2.1-SNAPSHOT/xml
This resulted in the following error message:
karaf@root()> feature:repo-add mvn:org.apache.karaf.examples/karaf-rest-example-features/4.2.1-SNAPSHOT/xml
Adding feature url mvn:org.apache.karaf.examples/karaf-rest-example-features/4.2.1-SNAPSHOT/xml
Error executing command: Error resolving artifact org.apache.karaf.examples:karaf-rest-example-features:xml:4.2.1-SNAPSHOT: [Could not find artifact org.apache.karaf.examples:karaf-rest-example-features:xml:4.2.1-SNAPSHOT in apache (http://repository.apache.org/content/groups/snapshots-group/), Could not find artifact org.apache.karaf.examples:karaf-rest-example-features:xml:4.2.1-SNAPSHOT in ops4j.sonatype.snapshots.deploy (https://oss.sonatype.org/content/repositories/ops4j-snapshots/)] : mvn:org.apache.karaf.examples/karaf-rest-example-features/4.2.1-SNAPSHOT/xml
See here for a screen shot of the error message 
Question: how can I get a simple rest service to start in apache karaf?
(does not have to be the example exactly, I would be happy to have some hello world example which is accessible via http.)
Thank you very much for your support!
Update1: I tried to install the bundles by directly adding them to my deploy directory. I am getting the following errors when trying to start up the bundles. What exactly am i missing here?
Update2: I have installed all the missing requirements but i still get the following error. I am very sorry for these tedious questions, but why is the org.osgi.service.blueprint requirement still missing even though the bundle is clearly installed and running (id 177)?
So to see some info why a bundle isn't active you can use bundle:diag command. As can be seen from screenshot your bundle has missing requirement com.fasterxml.jackson.jaxrs.json.
You can add missing libraries to <Import-Package> section of your maven-bundle-plugin or install these to apache karaf. This command will install dependency directly from maven repo:
install -s mvn:com.fasterxml.jackson.jaxrs/jackson-jaxrs-json-provider/2.9.7
Also you can download a bundle file from here and install it manually by putting jar to deploy dir
see this link for more info