There is often the need to instantiate a single bean instance in the spring config file such that the bean is an array of strings that can be referenced in multiple other places. I tried the following which wouldn't work:

<bean id="reusableStringArray" class="[Ljava.lang.String">
  <list>
      <value>a</value>
      <value>b</value>
  </list>
</bean>

A similar requirement is to create a single bean instance which is a java.util.Properties object in the application context. It turns out I can define a list instead of a string-array. It does not matter because spring can transform the list to a string-array if necessary. Example:

<bean id="strings" class="java.util.ArrayList">
<constructor-arg index="0">
  <list>
     <value>a</value>
     <value>b</value>
  </list>
</constructor-arg>
</bean>

Similarly one should be able to create a Properties instance via a map element. Thanks to Andreas on this.

Also, Carlos Sanchez has a nice blog on this subject.

http://static.springframework.org/spring/docs/1.2.x/reference/beans.html#d0e2331