Minor Description
When I create a custom distribution with the attached pom, which tries to exchange Pax-Web with a newer version, Pax-Web gets installed twice:
karaf@root()> feature:list -i Name | Version | Required | State | Repository | Description --------------------+------------------+----------+---------+-------------------------+-------------------------------------------------- pax-jetty | 9.3.14.v20161028 | | Started | org.ops4j.pax.web-6.0.4 | Provide Jetty engine support pax-http-jetty | 6.0.4 | | Started | org.ops4j.pax.web-6.0.4 | pax-http | 6.0.4 | | Started | org.ops4j.pax.web-6.0.4 | Implementation of the OSGI HTTP Service pax-http-whiteboard | 6.0.4 | | Started | org.ops4j.pax.web-6.0.4 | Provide HTTP Whiteboard pattern support pax-war | 6.0.4 | | Started | org.ops4j.pax.web-6.0.4 | Provide support of a full WebContainer pax-http-tomcat | 6.0.4 | | Started | org.ops4j.pax.web-6.0.4 | Provide Tomcat support pax-war-tomcat | 6.0.4 | x | Started | org.ops4j.pax.web-6.0.4 | aries-proxy | 4.1.1 | | Started | standard-4.1.1 | Aries Proxy aries-blueprint | 4.1.1 | | Started | standard-4.1.1 | Aries Blueprint feature | 4.1.1 | | Started | standard-4.1.1 | Features Support shell | 4.1.1 | | Started | standard-4.1.1 | Karaf Shell shell-compat | 4.1.1 | | Started | standard-4.1.1 | Karaf Shell Compatibility deployer | 4.1.1 | | Started | standard-4.1.1 | Karaf Deployer bundle | 4.1.1 | | Started | standard-4.1.1 | Provide Bundle support config | 4.1.1 | | Started | standard-4.1.1 | Provide OSGi ConfigAdmin support diagnostic | 4.1.1 | | Started | standard-4.1.1 | Provide Diagnostic support instance | 4.1.1 | | Started | standard-4.1.1 | Provide Instance support jaas | 4.1.1 | | Started | standard-4.1.1 | Provide JAAS support log | 4.1.1 | | Started | standard-4.1.1 | Provide Log support package | 4.1.1 | | Started | standard-4.1.1 | Package commands and mbeans service | 4.1.1 | | Started | standard-4.1.1 | Provide Service support system | 4.1.1 | | Started | standard-4.1.1 | Provide System support kar | 4.1.1 | | Started | standard-4.1.1 | Provide KAR (KARaf archive) support ssh | 4.1.1 | | Started | standard-4.1.1 | Provide a SSHd server on Karaf management | 4.1.1 | | Started | standard-4.1.1 | Provide a JMX MBeanServer and a set of MBeans in eventadmin | 4.1.1 | x | Started | standard-4.1.1 | OSGi Event Admin service specification for event- scr | 4.1.1 | | Started | standard-4.1.1 | Declarative Service support wrap | 0.0.0 | | Started | standard-4.1.1 | Wrap URL handler standard | 4.1.1 | x | Started | standard-4.1.1 | Wrap feature describing all features part of a st pax-jetty | 9.3.14.v20161028 | | Started | org.ops4j.pax.web-6.0.3 | Provide Jetty engine support pax-http-jetty | 6.0.3 | | Started | org.ops4j.pax.web-6.0.3 | pax-http-whiteboard | 6.0.3 | | Started | org.ops4j.pax.web-6.0.3 | Provide HTTP Whiteboard pattern support pax-war | 6.0.3 | | Started | org.ops4j.pax.web-6.0.3 | Provide support of a full WebContainer pax-http-tomcat | 6.0.3 | | Started | org.ops4j.pax.web-6.0.3 | Provide Tomcat support
A workaround would be to uncomment the tree lines in the pom and explicitly add almost all dependent Pax-Web features to the distribution.