[einrealist]

Adobe is the main contributor to Apache Sling, which uses Apache Felix and Apache Jackrabbit (and Oak since AEM 6). And Lucene is the default index for AEM (formerly known as Day Communique). There are other Apache projects used, too, like Tika.

[justincormack]

And not unrelatedly, Roy Fielding is now at Adobe (formerly at Day), who started Apache the webserver and was chair of the Apache foundation.