How I do external configuration using a global command line variable in Java/Spring

gistfile1.txt

	<context:annotation-config />
	
	<!-- System Properties -->
	<context:property-placeholder
		system-properties-mode="OVERRIDE" ignore-unresolvable="true" />
	<!-- Externally Configured Properties -->
	<util:list id="configLocations">
		<value>classpath:defaultConfig.properties</value>
		<value>file:${externalConfiguration:}</value>
	</util:list>

	<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
		p:ignoreResourceNotFound="true" p:locations-ref="configLocations" />
	<bean id="appConfig" class="org.springframework.beans.factory.config.PropertiesFactoryBean"
		p:ignoreResourceNotFound="true" p:locations-ref="configLocations" />