contextNamespaceHandlerTests-system.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans-4.2.xsd
				http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context-4.2.xsd
				http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util-4.2.xsd">

	<util:properties id="placeholderProps">
		<prop key="foo">bar</prop>
	</util:properties>

	<context:property-placeholder properties-ref="placeholderProps" system-properties-mode="OVERRIDE" value-separator="?"/>

	<bean id="string" class="java.lang.String">
		<constructor-arg value="${foo}"/>
	</bean>

	<bean id="fallback" class="java.lang.String">
		<constructor-arg value="${bar?none}"/>
	</bean>

</beans>