autowire byType according to Spring 4.1.6 to Documentation -

allows property autowired if 1 bean of property type exists in container. if more 1 exists, fatal exception thrown, indicates may not use bytype autowiring bean. if there no matching beans, nothing happens; property not set. - spring reference guid 4.1.6

<bean id="person" class="autowire.person" autowire="bytype" />  <bean id="invisible" class="autowire.ability" >     <property name="skill" value="invisible" /> </bean>  <bean id="invisible2" class="autowire.ability" >     <property name="skill" value="invisible" /> </bean> 

class definitions:

package autowire;  public class person  { private ability ability; //... }  package autowire;  public class ability {      private string skill;      public string getskill() {         return skill;     }      public void setskill(string skill) {         this.skill = skill;     }  } 

i able define 2 beans of same type of class "autowire.ability". didnt fatal exception. understanding correct ?

you're there (to error). need tell spring class attributes need autowired. annotate person.ability @autowired , should error.

import org.springframework.beans.factory.annotation.autowired;  public class person  {   @autowired   private ability ability;   //... } 

or better create constructor , autowire it, injecting attributes considered bad practice.

public class person  {   private ability ability;    @autowired   public person(ability ability) {     this.ability = ability;   }   //... } 

spring doesn't assume attributes need injected (autowired) need specify ones want inject.