In Spring, you can uses this special <null /> tag to pass a “null” value into constructor argument or property.
The wrong way to inject a null into constructor argument, a really common mistake, and nice try :)
<bean id="defaultMongoTypeMapper1" class="org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper"> <constructor-arg name="typeKey" value="null" /> </bean>Correct way.
<bean id="defaultMongoTypeMapper" class="org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper"> <constructor-arg name="typeKey"> <null /> </constructor-arg> </bean>The wrong way to inject null value into property.
<bean id="myConverter" class="com.mkyong.convert.MoneyConverter"> <property name="typeMapper" value="null" /> </bean>Correct way.
<bean id="myConverter" class="com.mkyong.convert.MoneyConverter"> <property name="typeMapper"><null/></property> </bean>
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