In the same vein as my ‘Jetty in 3 lines’, here is Solr in 3 lines -
gem install solr_sail
A Solr config is extracted and all 57 jar dependencies will be
automatically downloaded as part of the install step. In the start step,
the Jars are automatically loaded into the classpath and Solr is
started. To make this work, it only takes 3 Java classes (two are used
for extracting the Solr config) and 2 Ruby (excluding the version file).
My rambling blog post with more details -