SpringApplication class not found

[t-rad679]

Hey there!

I'm getting ClassNotFoundExceptions for SpringApplication when I do either bazel run or java -jar app.jar for my springboot target. Note that I am using Spring Boot 3 and I have specified the JarLauncher class as instructed, and I'm pretty sure I have the correct dependencies (though maybe there's some kind of incompatibility among the versions of them). I took a look inside the jar, as well, and see that the jar containing SpringApplication is present (processed_spring-boot-3.4.4.jar) in /BOOT-INF/lib. I noticed in springboot.bzl it says that @SpringBootApplication should be present in /BOOT-INF/classes, which it is not. This is the only lead I have as to what is going wrong, even though the missing class is not the same as the one in the ClassNotFoundException. Do y'all have any advice? Is it possible this is a bug?

[t-rad679]

Oh, I also ran into a seemingly unrelated issue with syncing Bazel in IntelliJ where it said Turbine is not supported by lombok, and I resolved it by disabling java header compilation.

Note that my java version for the project as specified in the .bazelrc is 21, and the Bazel server java version (--java_serverbase)is set to the MacOS builtin java 24 SDK (I had to specify this to get around cert issues with my work proxy). I set the project java version with the following flags:

• java_language_version
• tool_java_language_version
• java_runtime_version
• tool_java_runtime_version

In case it wasn't assumed, bazel build completes successfully and produces the expected jar, which is the jar I was talking about having looked inside above.

[plaird]

Ok, strange. I just added a simple utility that we have used internally for cases like this.

https://github.com/salesforce/rules_spring/tree/main/tools/jar_explode

Please run the jar_explode.sh script on your springboot application, and then find SpringApplication.class on the filesystem. In helloworld, you will see output like:

% cd tools/jar_explode
% ./jar_explode.sh ../../bazel-bin/examples/helloworld/helloworld.jar
% cd /tmp/bazel/springbootexplode 
% find . -name SpringApplication.class
./processed_spring-boot-3.3.5.jar/org/springframework/boot/SpringApplication.class

[t-rad679]

And FYI I am using the newest version of rules_spring in BCR. I also copied the springboot_required_deps and am using that (I wasn't able to get referencing it directly from the rules_spring repo to work).

[t-rad679]

When I pulled the dependencies from Maven Central instead of our internal Artifactory proxy to Maven Central, it got past the error X_X.

[t-rad679]

After looking more closely at the jar gists and thinking about the problem, I have a hunch the issue may have to do with the Spring loader not liking the paths to the jars including the Artifactory path. I'm gonna try to manually make the paths match the ones from when I use maven central and see if it fixes it. If it does, I feel like I should file a bug. Maybe I can even fix it myself.

[t-rad679]

Ok I know I've written a lot here, but I modified springboot_pkg.sh to just drop all the dep jars for bazel-out and the else case into the base BOOT-INF/lib and indeed the application starts when I use the modified version. I'm not sure exactly what about the paths cause it to fail. My only guess is that one of the special characters used for specifying credentials throws something off in the Spring Boot class loading. I wish it had better failure logging. Anyway I'm gonna file a bug. Would love to discuss a solution with you.

In the meantime, since this is greenfield development and we can access maven central from our dev machines, we're going to just point there...but in the long run we're going to need to point to artifactory. I'm surprised this issue has never come up.

[plaird]

Great find!