In Spring Boot 3 how to benefit from Spring AOT with a regular JVM application?

Question

Spring Boot 3 will release in November 2022. The release candidate 2 has already been released.

Spring Boot 3 will ship with Spring AOT. Spring AOT generates additional source code so that reflection calls will be avoided.

Spring AOT was introduced to generate GraalVM Native Images. However, in theory Spring AOT could also be used for regular JVM applications to speed up the start-up process (since regular calls should be faster than reflection calls).

Unfortunately, I didn't find anything about how to use Spring AOT for regular JVM applications in the Spring Boot 3 reference documentation. Do you know how I can profit from Spring AOT in a regular JVM application?

Answer 1

You can run it with :

java -DspringAot=true -jar myapplication-0.0.1-SNAPSHOT.jar

Also check documentation for :

AOT runtime modes

Any application using Spring AOT can use the springAot System property in order to use the AOT classes with a regular JVM. This is mainly useful for debugging purposes in case of issues during native image generation.

For running an application with gradle bootRun or mvn spring-boot:run, configure your build as following:

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <!-- ... -->
        <systemPropertyVariables>
            <springAot>true</springAot>
        </systemPropertyVariables>
    </configuration>
</plugin>