Few steps for creating your own tomcat bundle from Liferay Source.

• Extract plain  tomcat .
• Rename apache- tomcat-7.0.23  to tomcat-7.0.23(tomcat-[version]).
• Download/checkout liferay source from https://lportal.svn.sourceforge.net/svnroot/lportal/portal/.
• Import this in eclipse
• Create app.server[userName].properties in portal-trunk(userName-User Name of your PC)
• Override three properties in above file

1. app.server.parent.dir =Parent directory path of tomcat
2. app.server.tomcat.portal.dir=Absolute path of portal-trunk/portal-web/docroot
3. app.server.tomcat.version=tomcat version

Eg. Suppose your source code in C:/WorkSpace folder & tomcat in C:/deployment folder with name tomcat-7.0.23.

1. app.server.parent.dir =C:/deployment (don’t consider tomcat-7.0.23 in this path)
2. app.server.tomcat.portal.dir = C:/WorkSpace/portal-trunk/portal-web/docroot
3. app.server.tomcat.version =7.0.23

• Then build ant all.
• If it will throw out of memory then set VM arguments to -Xms512m or more

Right click of build.xml -> Run As -> 2 Ant Build -> JRE here you will find VM arguments.

• Copy & replace catalina.properties from liferay bundle/conf  to tomcat/conf
• Create portal-ext.properties in \tomcat-[version]\webapps\ROOT\WEB-INF\classes

Copy following configurations in portal-ext.properties

1. jdbc.default.driverClassName=com.mysql.jdbc.Driver
2. jdbc.default.url=jdbc:mysql://localhost/[ DN_NAME]?useUnicode=true&characterEncoding=UTF-8&useFastDateParsing=false
3. jdbc.default.username=root
4. jdbc.default.password=root

change properties as per your database.