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Spring - Injecting a Bean as a JDK interface based Proxy Object

[Last Updated: Dec 22, 2023]

In out last example, instead of using ScopedProxyMode.TARGET_CLASS, we can specify proxyMode as ScopedProxyMode.INTERFACES with @Scope annotation.

This mode needs to be specified if we are autowiring interface rather than a concrete class.

Spring injects JDK interface based proxy rather than CGLIB class based proxy.

This example is a modification of our previous example. We are going to create an interface for our prototype bean so that it can be injected into wider scoped singleton bean using JDK interface based proxy mode.


Example


Interface for prototype bean

package com.logicbig.example;

public interface IPrototype {

  String getDateTime();
}

Prototype bean

package com.logicbig.example;

import java.time.LocalDateTime;

public class MyPrototypeBean implements IPrototype {

  private String dateTimeString = LocalDateTime.now().toString();

  @Override
  public String getDateTime() {
      return dateTimeString;
  }
}

Singleton bean

package com.logicbig.example;

import org.springframework.beans.factory.annotation.Autowired;

public class MySingletonBean {

  @Autowired
  private IPrototype prototypeBean;

  public void showMessage(){
      System.out.println("Hi, the time is "+prototypeBean.getDateTime());
  }
}

Main class

package com.logicbig.example;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.*;

@Configuration
public class AppConfig {

  @Bean
  @Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE,
                      proxyMode = ScopedProxyMode.INTERFACES)
  public IPrototype prototypeBean () {
      return new MyPrototypeBean();
  }

  @Bean
  public MySingletonBean singletonBean () {
      return new MySingletonBean();
  }

  public static void main (String[] args) throws InterruptedException {
      AnnotationConfigApplicationContext context =
                          new AnnotationConfigApplicationContext(AppConfig.class);
      MySingletonBean bean = context.getBean(MySingletonBean.class);
      bean.showMessage();
      Thread.sleep(1000);

      bean.showMessage();
  }
}

Output

Hi, the time is 2021-05-05T02:09:20.612
Hi, the time is 2021-05-05T02:09:21.634

Example Project

Dependencies and Technologies Used:

  • spring-context 6.1.2 (Spring Context)
     Version Compatibility: 3.2.3.RELEASE - 6.1.2Version List
    ×

    Version compatibilities of spring-context with this example:

    • 3.2.3.RELEASE
    • 3.2.4.RELEASE
    • 3.2.5.RELEASE
    • 3.2.6.RELEASE
    • 3.2.7.RELEASE
    • 3.2.8.RELEASE
    • 3.2.9.RELEASE
    • 3.2.10.RELEASE
    • 3.2.11.RELEASE
    • 3.2.12.RELEASE
    • 3.2.13.RELEASE
    • 3.2.14.RELEASE
    • 3.2.15.RELEASE
    • 3.2.16.RELEASE
    • 3.2.17.RELEASE
    • 3.2.18.RELEASE
    • 4.0.0.RELEASE
    • 4.0.1.RELEASE
    • 4.0.2.RELEASE
    • 4.0.3.RELEASE
    • 4.0.4.RELEASE
    • 4.0.5.RELEASE
    • 4.0.6.RELEASE
    • 4.0.7.RELEASE
    • 4.0.8.RELEASE
    • 4.0.9.RELEASE
    • 4.1.0.RELEASE
    • 4.1.1.RELEASE
    • 4.1.2.RELEASE
    • 4.1.3.RELEASE
    • 4.1.4.RELEASE
    • 4.1.5.RELEASE
    • 4.1.6.RELEASE
    • 4.1.7.RELEASE
    • 4.1.8.RELEASE
    • 4.1.9.RELEASE
    • 4.2.0.RELEASE
    • 4.2.1.RELEASE
    • 4.2.2.RELEASE
    • 4.2.3.RELEASE
    • 4.2.4.RELEASE
    • 4.2.5.RELEASE
    • 4.2.6.RELEASE
    • 4.2.7.RELEASE
    • 4.2.8.RELEASE
    • 4.2.9.RELEASE
    • 4.3.0.RELEASE
    • 4.3.1.RELEASE
    • 4.3.2.RELEASE
    • 4.3.3.RELEASE
    • 4.3.4.RELEASE
    • 4.3.5.RELEASE
    • 4.3.6.RELEASE
    • 4.3.7.RELEASE
    • 4.3.8.RELEASE
    • 4.3.9.RELEASE
    • 4.3.10.RELEASE
    • 4.3.11.RELEASE
    • 4.3.12.RELEASE
    • 4.3.13.RELEASE
    • 4.3.14.RELEASE
    • 4.3.15.RELEASE
    • 4.3.16.RELEASE
    • 4.3.17.RELEASE
    • 4.3.18.RELEASE
    • 4.3.19.RELEASE
    • 4.3.20.RELEASE
    • 4.3.21.RELEASE
    • 4.3.22.RELEASE
    • 4.3.23.RELEASE
    • 4.3.24.RELEASE
    • 4.3.25.RELEASE
    • 4.3.26.RELEASE
    • 4.3.27.RELEASE
    • 4.3.28.RELEASE
    • 4.3.29.RELEASE
    • 4.3.30.RELEASE
    • 5.0.0.RELEASE
    • 5.0.1.RELEASE
    • 5.0.2.RELEASE
    • 5.0.3.RELEASE
    • 5.0.4.RELEASE
    • 5.0.5.RELEASE
    • 5.0.6.RELEASE
    • 5.0.7.RELEASE
    • 5.0.8.RELEASE
    • 5.0.9.RELEASE
    • 5.0.10.RELEASE
    • 5.0.11.RELEASE
    • 5.0.12.RELEASE
    • 5.0.13.RELEASE
    • 5.0.14.RELEASE
    • 5.0.15.RELEASE
    • 5.0.16.RELEASE
    • 5.0.17.RELEASE
    • 5.0.18.RELEASE
    • 5.0.19.RELEASE
    • 5.0.20.RELEASE
    • 5.1.0.RELEASE
    • 5.1.1.RELEASE
    • 5.1.2.RELEASE
    • 5.1.3.RELEASE
    • 5.1.4.RELEASE
    • 5.1.5.RELEASE
    • 5.1.6.RELEASE
    • 5.1.7.RELEASE
    • 5.1.8.RELEASE
    • 5.1.9.RELEASE
    • 5.1.10.RELEASE
    • 5.1.11.RELEASE
    • 5.1.12.RELEASE
    • 5.1.13.RELEASE
    • 5.1.14.RELEASE
    • 5.1.15.RELEASE
    • 5.1.16.RELEASE
    • 5.1.17.RELEASE
    • 5.1.18.RELEASE
    • 5.1.19.RELEASE
    • 5.1.20.RELEASE
    • 5.2.0.RELEASE
    • 5.2.1.RELEASE
    • 5.2.2.RELEASE
    • 5.2.3.RELEASE
    • 5.2.4.RELEASE
    • 5.2.5.RELEASE
    • 5.2.6.RELEASE
    • 5.2.7.RELEASE
    • 5.2.8.RELEASE
    • 5.2.9.RELEASE
    • 5.2.10.RELEASE
    • 5.2.11.RELEASE
    • 5.2.12.RELEASE
    • 5.2.13.RELEASE
    • 5.2.14.RELEASE
    • 5.2.15.RELEASE
    • 5.2.16.RELEASE
    • 5.2.17.RELEASE
    • 5.2.18.RELEASE
    • 5.2.19.RELEASE
    • 5.2.20.RELEASE
    • 5.2.21.RELEASE
    • 5.2.22.RELEASE
    • 5.2.23.RELEASE
    • 5.2.24.RELEASE
    • 5.2.25.RELEASE
    • 5.3.0
    • 5.3.1
    • 5.3.2
    • 5.3.3
    • 5.3.4
    • 5.3.5
    • 5.3.6
    • 5.3.7
    • 5.3.8
    • 5.3.9
    • 5.3.10
    • 5.3.11
    • 5.3.12
    • 5.3.13
    • 5.3.14
    • 5.3.15
    • 5.3.16
    • 5.3.17
    • 5.3.18
    • 5.3.19
    • 5.3.20
    • 5.3.21
    • 5.3.22
    • 5.3.23
    • 5.3.24
    • 5.3.25
    • 5.3.26
    • 5.3.27
    • 5.3.28
    • 5.3.29
    • 5.3.30
    • 5.3.31
    • Compatible Java Version: 17+
    • 6.0.0
    • 6.0.1
    • 6.0.2
    • 6.0.3
    • 6.0.4
    • 6.0.5
    • 6.0.6
    • 6.0.7
    • 6.0.8
    • 6.0.9
    • 6.0.10
    • 6.0.11
    • 6.0.12
    • 6.0.13
    • 6.0.14
    • 6.0.15
    • 6.1.0
    • 6.1.1
    • 6.1.2

    Versions in green have been tested.

  • JDK 17
  • Maven 3.8.1

Injecting a Bean as a JDK interface based Proxy Object Select All Download
  • scoped-proxy-interface-example
    • src
      • main
        • java
          • com
            • logicbig
              • example
    • pom.xml

    See Also