java - Issue while autowiring strongly typed collections -

i using spring 3.2.2. facing issue while autowring collection spring's bytype autowiring mode. have created below example.

bean defination:

package com.springaction.testmultidimesionalcollection;  import java.util.arraylist;  /**  * @author jinesh  *  */ public class address {      arraylist<country> country;      public arraylist<country> getcountry() {         return country;     }     /**      * @param country country set      */     public void setcountry(arraylist<country> country) {         this.country = country;     }   } 

below spring configuration file testmultidimensionalcollection.xml

<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-3.0.xsd     http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">       <bean id="addressmiddleeast" class="com.springaction.testmultidimesionalcollection.address" autowire="bytype">      </bean>       <bean id="countrychina" class="com.springaction.testmultidimesionalcollection.country">         <property name="countryname" value="china" />     </bean>     <bean id="countryindia" class="com.springaction.testmultidimesionalcollection.country">         <property name="countryname" value="india" />     </bean>     <bean id="countryaus" class="com.springaction.testmultidimesionalcollection.country">         <property name="countryname" value="australia" />     </bean>     <bean id="middeastcountryquatar" class="com.springaction.testmultidimesionalcollection.country">         <property name="countryname" value="quatar" />     </bean>     <bean id="middeastcountryisrael" class="com.springaction.testmultidimesionalcollection.country">         <property name="countryname" value="israel" />     </bean>     <bean id="middeastcountryyemen" class="com.springaction.testmultidimesionalcollection.country">         <property name="countryname" value="yemen" />     </bean>  </beans> 

here have strong type collection in address class. elements of country supposed added inside country properties arraylist when executing below code getting null pointer exception.

package com.springaction.testmultidimesionalcollection;  import org.springframework.context.applicationcontext; import org.springframework.context.support.classpathxmlapplicationcontext;  /**  * @author jinesh  *  */  public class testmultidimensionalmain {      /**      * @param args      */     public static void main(string[] args) {         // todo auto-generated method stub         applicationcontext context =  new classpathxmlapplicationcontext("com/springaction/testmultidimesionalcollection/testmultidimensionalcollection.xml");         address addrs=(address)context.getbean("addressmiddleeast");         system.out.println("address size:" + addrs.getcountry().size());    } } 

i not able understand, why spring not able automatically detect country beans , add them array list property of address bean? have missed in configuration?

you haven't requested autowired. bean

<bean id="addressmiddleeast" class="com.springaction.testmultidimesionalcollection.address" autowire="bytype"> </bean>  

and class

public class address {      arraylist<country> country;      public arraylist<country> getcountry() {         return country;     }     /**      * @param country country set      */     public void setcountry(arraylist<country> country) {         this.country = country;     } } 

simply has property setters/getters. need use @autowired (or related annotations).

public class address {     @autowired     arraylist<country> country; 

if can't use @autowired (why not???), need create bean of type list has reference each of country beans, in (now deleted) tichodrama's answer.

this explained in spring ioc documentation here