If you require a webapp to always run in https mode using a SSL key, then you need to add the following to your WEB-INF/web.xml configuration.
<security-constraint>
<web-resource-collection>
<web-resource-name>jsp</web-resource-name>
<url-pattern>*.htm</url-pattern>
<url-pattern>*.html</url-pattern>
</web-resource-collection>
<user-data-constraint>
<transport-guarantee>CONFIDENTIAL</transport-guarantee>
</user-data-constraint>
</security-constraint>
