spring-framework does not conform to @PostConstruct documentation #30494
Description
I think spring-framework 6.0.7 does not fully conform to the contract defined by the jakarta.annotation.PostConstruct annotation (from jakarta.annotation-api-2.1.1.jar).
The Javadoc of the annotation says: "Only one method in a given class can be annotated with this annotation.".
However, it is possible to annotate at least two methods of a given class which is registered as a @Component or @Bean with this annotation and all annotated methods are executed after the bean is initialized after calling SpringApplication.run().
Shouldn't the Spring application refuse to initialize such a bean if it finds more than one method annotated with @PostConstruct (although this would restrict developers to only having one @PostConstruct method per bean class)?
This is my POM:
<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.0.5</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.tutego</groupId>
<artifactId>date4u</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>date4u</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>17</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.shell</groupId>
<artifactId>spring-shell-starter</artifactId>
<version>3.0.0-M2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
This is my bean class:
import org.springframework.stereotype.Component;
import jakarta.annotation.PostConstruct;
@Component
public class MyComponent {
@PostConstruct
void postConstruct1() {
System.out.println("post construct1");
}
@PostConstruct
void postConstruct2() {
System.out.println("post construct2");
}
}
And my application class:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Date4uApplication {
public static void main(String[] args) {
SpringApplication.run(Date4uApplication.class, args);
}
}