xml - Cannot locate BeanDefinitionDecorator for element [set] -

i have spring xml config schema:

<?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:util="http://www.springframework.org/schema/util"        xsi:schemalocation="http://www.springframework.org/schema/beans         http://www.springframework.org/schema/beans/spring-beans-3.2.xsd         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">  

with property bean definition:

 <property name="airdates">       <util:set set-class="java.util.treeset">           <ref bean="first_event_datetime"/>       </util:set>  </property>   <bean         name="first_event_datetime"         class="java.time.localdatetime"         factory-method="of">     <constructor-arg type="int" value="2020"/>     <constructor-arg type="int" value="6"/>     <constructor-arg type="int" value="15"/>     <constructor-arg type="int" value="19"/>     <constructor-arg type="int" value="30"/> </bean> 

target of injection navigableset setter , getter accordingly

private navigableset<localdatetime> airdates = new treeset<>();  

---

the problem is: 1) ide highlights util:set , says bean must 1 of these types:

bean must 1 of these types: java.time.localdatetime or java.util.navigableset

2) spring execution says me:

cannot locate beandefinitiondecorator element [set]

do have ideas how solve problem?

please provide definition of first_event_datetime

update: following definition works @ environment:

xml:

... <bean     name="first_event_datetime" class="java.time.localdatetime" factory-method="of">     <constructor-arg type="int" value="2020"/>     <constructor-arg type="int" value="6"/>     <constructor-arg type="int" value="15"/>     <constructor-arg type="int" value="19"/>     <constructor-arg type="int" value="30"/> </bean> ... <bean id="client" class="<my package>.client"     <property name="airdates">         <util:set set-class="java.util.treeset">             <ref bean="first_event_datetime"/>         </util:set>     </property> </bean>  

java:

import java.time.localdatetime; import java.util.navigableset;  public class client {    private navigableset<localdatetime> airdates;    public navigableset<localdatetime> getairdates() {     return airdates;   }    public void setairdates(navigableset<localdatetime> airdates) {     this.airdates = airdates;   }   ... }