I need to add search functionality to my Java webapp running on tomcat, along with the database as well on the same machine.
Since I\'m planning to use Solr on this
You can setup Solr as another "web service" in the same Tomcat your are using for your web app, do the proper configuration and use it via the HTTP/REST interface. Alternatively you can also use the out-of-the-box Jetty container. Check for more details on how to install here: http://wiki.apache.org/solr/SolrInstall.
I do not believe using embedded solr will be consuming (much) less resources... if you really do not want to separate things (application and solr), probably you should be looking on Lucene directly and not Solr, since the main goal of Solr is to allow the creation of web service interface for Lucene, which can be accessed from any application (it has several other extensions - http://lucene.apache.org/solr/features.html, but the core of Solr is the Lucene java search library).
The page you reference answers your question. You run Solr on the same machine in its own JVM, as a service, and interact with it over HTTP (to localhost).