Done: I figured it out. In Solr 4, we need to create .xml file in context folder for each webapps.war added ....
For example: In context folder there is a file solr.xml : copy that file and name it to same as your new webapps.war file you already added into webapps folder
Edit the new .xml file ; change context path to : /your webapps name change .war file name to your .war file and if you want tomcat to extract it to some folder specitiy that. For e.g. solr extract it in solr-webapps. hyou can extract it in yourwebapp-webapps.
Remember if you use same extract location then one of the .war file service won't start.
I hope I am clear....