apache tomcat - how to change the default port

open your server.xml file (in ubuntu tomcat installation it is /etc/tomcat7/server.xml)
then locate the code similar to

   < Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />

or

    <Connector port="8080" maxHttpHeaderSize="8192"
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" redirectPort="8443" acceptCount="100"
               connectionTimeout="20000" disableUploadTimeout="true" />


then change the port number to any number you like.