Spring can you autowire inside an abstract class

Question

Spring is failing to autowire my object  Is it possible to autowire an object within an abstract class  Assume all schemas are supplied in application-context xml  Question  What annotation should be on the base and extending classes  if any   Service  Component   Example  abstract class SuperMan         Autowire     private DatabaseService databaseService       abstract void Fly         protected void doSuperPowerAction Thing thing               busy code          databaseService save thing              Extending class  public class SuperGirl extends SuperMan         Override     public void Fly               busy code            public doSomethingSuperGirlDoes                busy code          doSuperPowerAction thing           application-context xml   lt context component-scan base-package  com baseLocation    gt   lt context annotation-config  gt

User · Accepted Answer

Normally  Spring should do the autowiring  as long as your abstract class is in the base-package provided for component scan    See this and this for further reference    Service and  Component are both stereotypes that creates beans of the annotated type inside the Spring container  As Spring Docs state       This annotation serves as a specialization of  Component  allowing for   implementation classes to be autodetected through classpath scanning

User · Answer

In my case  inside a Spring4 Application  i had to use a classic Abstract Factory Pattern for which i took the idea from - http   java-design-patterns com patterns abstract-factory   to create instances each and every time there was a operation to be done So my code was to be designed like   public abstract class EO        Autowired     protected SmsNotificationService smsNotificationService       Autowired     protected SendEmailService sendEmailService              protected abstract void executeOperation GenericMessage gMessage      public final class OperationsExecutor       public enum OperationsType           ENROLL  CAMPAIGN            private OperationsExecutor                public static Object delegateOperation OperationsType type  Object obj                 switch type                case ENROLL                  if  obj    null                        return new EnrollOperation                                      return EnrollOperation validateRequestParams obj               case CAMPAIGN                  if  obj    null                        return new CampaignOperation                                      return CampaignOperation validateRequestParams obj               default                  throw new IllegalArgumentException  OperationsType not supported                         Configurable dependencyCheck   true  public class CampaignOperation extends EO        Override     public void executeOperation GenericMessage genericMessage            LOGGER info  This is CAMPAIGN Operation      genericMessage             Initially to inject the dependencies in the abstract class I tried all stereotype annotations like  Component   Service etc but even though Spring context file had ComponentScanning for the entire package  but somehow while creating instances of Subclasses like CampaignOperation  the Super Abstract class EO was having null for its properties as spring was unable to recognize and inject its dependencies After much trial and error I used this    Configurable dependencyCheck   true    annotation and finally Spring was able to inject the dependencies and I was able to use the properties in the subclass without cluttering them with too many properties    lt context annotation-config   gt   lt context component-scan base-package  com xyz    gt    I also tried these other references to find a solution    http   www captaindebug com 2011 06 implementing-springs-factorybean html  WqF5pJPwaAN http   forum spring io forum spring-projects container 46815-problem-with-autowired-in-abstract-class https   github com cavallefano Abstract-Factory-Pattern-Spring-Annotation http   www jcombat com spring factory-implementation-using-servicelocatorfactorybean-in-spring https   www madbit org blog programming 1074 1074  sthash XEJXdIR5 dpbs Using abstract factory with Spring framework Spring Autowiring not working for Abstract classes Inject spring dependency in abstract super class Spring and Abstract class - injecting properties in abstract classes   Spring autowire dependency defined in an abstract class    Please try using    Configurable dependencyCheck   true    and update this post  I might try helping you if you face any problems

User · Answer

I have that kind of spring setup working  an abstract class with an autowired field  public abstract class AbstractJobRoute extends RouteBuilder         Autowired     private GlobalSettingsService settingsService    and several children defined with  Component annotation

User · Answer

What if you need any database operation in SuperGirl you would inject it again into SuperGirl   I think the main idea is using the same object reference in different classes  So what about this     There is no annotation about Spring in the abstract part  abstract class SuperMan         private final DatabaseService databaseService       public SuperMan DatabaseService databaseService         this databaseService   databaseService             abstract void Fly         protected void doSuperPowerAction Thing thing               busy code          databaseService save thing                 Component public class SuperGirl extends SuperMan    private final DatabaseService databaseService    Autowired public SuperGirl  DatabaseService databaseService         super databaseService        this databaseService   databaseService          Override public void Fly           busy code    public doSomethingSuperGirlDoes            busy code      doSuperPowerAction thing       In my opinion  inject once run everywhere

[spring] Spring can you autowire inside an abstract class?

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