springboot java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication

Hey,

When migrated to 2.3.0.RC1 the bootJar that is created by the bootJar task does not longer contains application classes nor Spring Boot ones.

I thought that something was changed because of introduction of the layered Jars but according to the doc:

By default, the bootJar task builds an archive that contains the application’s classes and dependencies in BOOT-INF/classes and BOOT-INF/lib respectively.

Environment: - JDK 14 - Gradle 6.4

Executing:

gradle clean bootJar

java -jar build/lib/****.jar

This gets the error as below which is expected as the classes are not bundled there.

Exception in thread "main" java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:109)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
    at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88)
Caused by: java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
    at com.tlt.quantum.registry.RegistrySearchServiceApplication.main(RegistrySearchServiceApplication.java:18)
    ... 8 more
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
    at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:435)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589)
    at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:129)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    ... 9 more

Comment From: wilkinsona

Thanks for the report. This looks like a duplicate of https://github.com/spring-projects/spring-boot/issues/21288. Are you using DevTools?

Comment From: aleksanderlech

Thanks for the report. This looks like a duplicate of #21288. Are you using DevTools?

I am, thank you for the fast response. I did the retest using today's 2.3.0.BUILD-SNAPSHOT and the problem seems to be fixed so we can consider the issue as closed :)

Comment From: snicoll

Thanks for the quick follow-up @aleksanderlech