My runtime environment is still on JDK1.4 but I like the Solr features related to how documents are ingested and indexed. Would I be able to index my documents using Solr offline on a recent version of the JDK, copy the index over and use it in my runtime environment with an older version of the JDK?
Version wise, Solr 1.4.0 uses Apache Lucene 2.9.1 which is JDK1.4 compatible. (but Solr itself requires JDK5).
Assuming what I’m trying to do is even possible, what features would I lose if I search Solr indices only with the Lucene API?
Yes, the Solr index is a standard Lucene index which you can open with “raw” Lucene, however you would lose all the features that Solr does for you, like faceting, caching, highlighting, etc.