When do I have to create new instance while using @Autowired

When do I have to create new instance while using @Autowired

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When do I have to create new instance while using @Autowired
Tag : java , By : unfool
Date : November 23 2020, 04:01 AM

I hope this helps you . When you instantiate a bean itself, it does not make it managed anymore and thus all of the @Autowired dependencies will not be processed. In order to make sure that dependencies are injected properly, you will need to instantiate the bean through the Spring context. Spring needs to instantiate the whole beans trail in order to perform the dependency injection properly. Please check the IoC details in this link: https://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/beans.html#beans-factory-class-ctor
Looking at your code, there are two ways to do this
public class RestApiApplication implements CommandLineRunner {

    private TaskScheduler ts;

    public static void main(String[] args) {
        SpringApplication.run(RestApiApplication.class, args);

    public void run(String... args) throws Exception {

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AutoWired Setters rather than AutoWired instance variables in Spring

Tag : java , By : barefootChild
Date : March 29 2020, 07:55 AM
may help you . Some observations from me (actually 3 years in Java EE):

@Autowired service is null but I need create new instance

Tag : java , By : Praetoriansentry
Date : March 29 2020, 07:55 AM
wish of those help I'm developing an app with Spring boot, I'm using the MVC model. I have an entity called A, which has its controller, service and repository. all right up here. , If you need to do some task periodically:
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application .class, args);

class Runner {

    private Service service;

    @Scheduled(cron = "0 */2 * * * ?") // execute every 2 hours
    public void run() {
        // put your logic here

@Autowired not work inside class that class instance create using reflection

Tag : java , By : user119985
Date : March 29 2020, 07:55 AM
should help you out Spring can't inject anything in an instance that you create yourself with new or via reflection.
One of the ways to do what you want would be to request the beans from the application context, something along the following lines:

private ApplicationContext applicationContext;

public void createUser(Class<?> beanClass) {
    ILogic logic = applicationContext.getBean(beanClass);

Is there way to reload autowired instance or replace autowired behavior in spring

Tag : java , By : Patastroph
Date : March 29 2020, 07:55 AM
wish helps you Your approach is very wrong. Autowiring is for connecting dependencies at startup. (It is actually discouraged these days, in favour of constructor argument injection.)
What you probably need is to have a @Service which retrieves the data model from the remote service. You then inject this service in the classes that need it to get the model.
public class ModelService {

  private final RestTemplate restTemplate;

  public ModelService(RestTemplate restTemplate) {
    this.restTemplate = restTemplate;

  @Cacheable(value = "model", key = "#root.methodName")
  public Model getModel() {

    MetadataReader metadataReader = new MetadataReader();
    String prismFormatJson = null;
    if (!isHasLatestTransformedJson()) {
        prismFormatJson = metadataReader.transformToPrismJson(restTemplate, environment);
    } else {
        prismFormatJson = getLastGoodPrismConfiguration();
    if (model != null) {
        return model;
    } else {
        return metadataReader.createModelForPrism(prismFormatJson);

  //... the rest of the code
  http://www.ehcache.org/v3 http://www.ehcache.org/schema/ehcache-core-3.0.xsd
  http://www.ehcache.org/v3/jsr107 http://www.ehcache.org/schema/ehcache-107-ext-3.0.xsd">

      <jsr107:cache name="model" template="model-cache"/>

  <cache-template name="model-cache">
      <ttl unit="minutes">10</ttl>

How can i create constructor with autowired and non autowired fields simultaniosly?

Tag : java , By : Fahad
Date : January 02 2021, 06:48 AM
like below fixes the issue You need to create your bean explicitly in the configuration. You don't need any autowiring inside your class:
public class EditSite{
  private final A a;
  private final B b;
  private final C c;

  private Site site;

  public EditSite(Site site, A a, B b , C c) {
      this.a = a;
      this.b = b;
      this.c = c;

  public void run(){ check(); }
  public void check(){}
public class EditSiteConfig {

  public EditSite editSite(A a, B b, C c){
    Site site = getSite(); //since site is not a bean, you need to get it manually
    return new EditSite(site, a, b, c);

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