Spring @Scope Annotation with Prototype Scope Example

In this article, we will discuss how to use the @Scope annotation with Prototype scope in a Spring Boot application.

Overview

The @Scope annotation is used to define the scope of a @Component class or a @Bean definition. The @Scope annotation can be used with all Spring bean scopes:

In this article, we will discuss how to use the @Scope annotation with Prototype scope with an example.

When a Spring bean is scoped as a prototype, the Spring IoC container creates a new bean instance every time a request is made for that bean. We can define the scope of a bean as a prototype using the @Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE) annotation.

We will demonstrate this example using annotation-based (@Component) as well as Java-based configuration (@Bean).

Spring @Scope Annotation + Prototype Scope + @Component Example

Let's create an example to demonstrate the usage of @Scope annotation with a prototype scope in a Spring application.

1. Create a Simple Maven Project

Create a simple Maven project using your favourite IDE. Below is the project structure for your reference:

2. The pom.xml File

Make sure to use Java 17 or later for Spring Framework 6:


<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0
    <groupId>org.example
    <artifactId>learn-spring-framework
    <version>1.0-SNAPSHOT
    <properties>
        <maven.compiler.source>17
        <maven.compiler.target>17
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework
            <artifactId>spring-core
            <version>6.0.6
        </dependency>
        <dependency>
            <groupId>org.springframework
            <artifactId>spring-context
            <version>6.0.6
        </dependency>
    </dependencies>
</project>

3. Create Spring Beans

MessageService Interface


package net.javaguides.spring.scope;

public interface MessageService {
    String getMessage();
    void setMessage(String message);
}

This interface defines two methods: getMessage() and setMessage(String message). Any class that implements this interface will need to provide implementations for these methods.

TwitterMessageService Class


package net.javaguides.spring.scope;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

@Component
@Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class TwitterMessageService implements MessageService {

    private String message;

    @Override
    public String getMessage() {
        return message;
    }

    @Override
    public void setMessage(String message) {
        this.message = message;
    }
}

In this class:

4. Annotation-Based Configuration

AppConfig Class


package net.javaguides.spring.scope;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan(basePackages = "net.javaguides.spring")
public class AppConfig {
}

In this class:

5. Running Spring Application

Application Class


package net.javaguides.spring.scope;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Application {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
        MessageService messageService = context.getBean(MessageService.class);
        messageService.setMessage("TwitterMessageService Implementation");
        System.out.println(messageService.getMessage());

        MessageService messageService1 = context.getBean(MessageService.class);
        System.out.println(messageService1.getMessage());
        context.close();
    }
}

In this class:

Output


TwitterMessageService Implementation
null

Explanation:

Spring @Scope Annotation + Prototype Scope + @Bean Example

Create MessageService Interface

MessageService Interface


package net.javaguides.spring.scope;

public interface MessageService {
    String getMessage();
    void setMessage(String message);
}

This interface remains the same as in the previous example.

Create TwitterMessageService Class

TwitterMessageService Class


package net.javaguides.spring.scope;

public class TwitterMessageService implements MessageService {

    private String message;

    @Override
    public String getMessage() {
        return message;
    }

    @Override
    public void setMessage(String message) {
        this.message = message;
    }
}

This class remains the same, but without @Component and @Scope annotations since we will configure it using Java-based configuration.

Java-based Configuration

AppConfig Class


package net.javaguides.spring.scope;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

@Configuration
public class AppConfig {

    @Bean
    @Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
    public MessageService messageService() {
        return new TwitterMessageService();
    }
}

In this class:

Running Spring Application

Application Class


package net.javaguides.spring.scope;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Application {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
        MessageService messageService = context.getBean(MessageService.class);
        messageService.setMessage("TwitterMessageService Implementation");
        System.out.println(messageService.getMessage());

        MessageService messageService1 = context.getBean(MessageService.class);
        System.out.println(messageService1.getMessage());
        context.close();
    }
}

This class remains the same as in the previous example.

Output


TwitterMessageService Implementation
null

Explanation:

Conclusion

In this article, we demonstrated how to use the @Scope annotation with Prototype scope in

Spring Boot applications. Using the prototype scope, we ensure that a new instance of the bean is created each time it is requested. This is particularly useful for beans that are stateful and need to be re-instantiated with every use.