Replace javax.annotation.Generated with custom gRPC annotation

[ejona86]

Since Java 9 dropped javax.annotation.Generated users have had to explicitly depend on a dep (typically Tomcat's annotation API) to get the annotation. It'd be nice not to need that the extra dep.

But even more important is that the removal of Generated from Java 9 upset the ecosystem as a whole and fragmented it so badly that I believe many tools are no longer assuming they can predict which annotation will be used and are heuristics like "is the annotation named 'Generated'" to determine whether they should it as generated code.

If we do an investigation and find that indeed all the tools we may care about (linters, static analyzers, IDEs) are observing Generated annotations in any package, then we can make our own io.grpc.Generated. Unfortunately, I expect the io.grpc.GrpcGenerated annotation may not suffice because its name is not exactly "Generated." We'll also need to figure out what retention it needs.

Tools to investigate (off the top of my head): Error Prone, IntelliJ, Eclipse, Android linter, Find Bugs, Checkstyle. The tools to investigate should be those that may be used by gRPC users, not just those directly used by gRPC maintainers.

javax.annotation.processing.Generated is not a relevant replacement; see #3633. I highly doubt jakarta.annotation.Generated would ever be appropriate, even with it being the new home for the annotation; it'd only have an advantage if Nullable goes that way as well, which seems unlikely. But that'd also take investigation of Kotlin and other null-caring tools.

[mkjensen]

FYI, I just tried upgrading a project from Spring Boot 2.7.4 to 3.0.0-M5.

One of the first issues I run into is:

[ERROR] <snip>/target/generated-sources/protobuf/grpc-java/<snip>ServiceGrpc.java:[12,17] error: cannot find symbol
[ERROR]   symbol:   class Generated
[ERROR]   location: package javax.annotation

Spring Boot 3 (Spring Framework 6) is moving to Jakarta EE 9 APIs (jakarta.) instead of EE 8 (javax.).

Depending on javax.annotation:javax.annotation-api:1.3.2 seems to be a workaround.

[slinkydeveloper]

Would it be possible to have an option to skip using javax.annotation as described by #9153?

[hutchig]

Our gRPC users in OpenLiberty are affected by this too when using EE9/EE10. The recommended solution is not to bundle an extra compile time [ADDED gh] dependency (why would users want to use Tomcat for this when they are used to OpenLiberty) but to use https://openliberty.io/blog/2021/03/17/eclipse-transformer.html (I would have added this to #9153 but it is locked.)

[gkwan-ibm]

IMO, using eclipse-transformer is a workaround. gRPC should support EE9/EE10 too.

[ejona86]

The recommended solution is not to bundle an extra dependency

Nobody needs to bundle an extra dependency. annotations-api is a compile-only dependency.

why would users want to use Tomcat for this when they are used to OpenLiberty

Nobody is depending on Tomcat. It is the annotations-api, which has no actual logic inside.

[hutchig]

I was aware of the retention policy of the annotation, I was referring to #9153 where you say "Our README recommends a compile-time dependency on org.apache.tomcat:annotations-api:6.0.53", by users I meant developers who would need something like the above reference in their build, apologies for my loose language causing any loss of meaning.

[xfl03]

A workaroud for Gradle, add it to dependencies in build.gradle：

implementation 'javax.annotation:javax.annotation-api:1.3.2'

[jorgerod]

Hello @ejona86

Is there any news on this issue? With the upgrade to Spring Boot 3, this is something blocking and will affect a lot of projects.

It would be nice if this annotation could be configurable or even to be able to skip this annotation.

Thank you very much

[ejona86]

I don't really see any new problem here. "Add the dependency like everyone else." You simply were able to side-step the dependency before. I do not recommend bundling; a project that compiles generated code is the one that should have the compile-only dependency.

Nothing is broken. Everyone can build. Nobody is blocked.

Nothing has changed in my original issue description: before we make any change we need to understand what tools are able to consume. Anyone is free to audit parts of the tooling ecosystem and reported their findings.

[gkwan-ibm]

As an application developer, I am developing a JavaEE 9 application and using gRPC. I used this maven project
pom.xml to generate and build a gRPC library by install goal but I got following error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.10.1:compile (default-compile) on project systemproto: Compilation failure
[ERROR] /Users/gkwan/tasks/.../systemproto/target/generated-sources/protobuf/grpc-java/.../systemproto/SystemServiceGrpc.java:[10,18] cannot find symbol
[ERROR]   symbol:   class Generated
[ERROR]   location: package javax.annotation

It is not a solution to use JEE 8 to build this library because it will not be compatible to my JEE9 application.

That's why I made this comment

[ejona86]

It is not a solution to use JEE 8 to build this library because it will not be compatible to my JEE9 application.

Compatible? If you add the snippet from the README:

<dependency> <!-- necessary for Java 9+ -->
  <groupId>org.apache.tomcat</groupId>
  <artifactId>annotations-api</artifactId>
  <version>6.0.53</version>
  <scope>provided</scope>
</dependency>

What error do you get? My understanding is that should work without issue.

[oburgosm]

It is not a solution to use JEE 8 to build this library because it will not be compatible to my JEE9 application.

Compatible? If you add the snippet from the README:

<dependency> <!-- necessary for Java 9+ -->
  <groupId>org.apache.tomcat</groupId>
  <artifactId>annotations-api</artifactId>
  <version>6.0.53</version>
  <scope>provided</scope>
</dependency>

What error do you get? My understanding is that should work without issue.

I don't understand why I need to add an artifact from 2017, that was renamed, to get my java-grpc application working. Furthermore when javax no longer exists. If you don't have inconvenience, we can contribute to solve this issue.

[ejona86]

It appears ErrorProne accepts any annotation, as long as the name is "Generated":
https://github.com/google/error-prone/blob/47c2b05c6a422c2fc0488dddfcfad56513c9bc04/check_api/src/main/java/com/google/errorprone/util/ASTHelpers.java#L1557

---

@oburgosm, we'd be happy for you to contribute. But that contribution would need to at least start with investigating what annotations the tooling ecosystem would accept, as mentioned when this issue was opened.

[Cypher01]

I use the following workaround to not require to include the useless javax.annotation-api dependency.

My project is based on Spring Boot 3.
I use Maven as my build system.
I use the protobuf-maven-plugin to generate Java code from protobuf

The code generation runs during the generate-sources phase. Before the code is compiled (compile phase), I edit the generated code, replacing javax by jakarta. The process-sources phase is the perfect fit for this task.
For replacement, I use the find-and-replace-maven-plugin, which does exactly what I need.

For all Maven users, simply add this to your plugins and you are good to go.

<plugin>
    <groupId>io.github.floverfelt</groupId>
    <artifactId>find-and-replace-maven-plugin</artifactId>
    <executions>
        <execution>
            <id>exec</id>
            <phase>process-sources</phase>
            <goals>
                <goal>find-and-replace</goal>
            </goals>
            <configuration>
                <replacementType>file-contents</replacementType>
                <baseDir>target/generated-sources/protobuf/</baseDir>
                <findRegex>javax</findRegex>
                <replaceValue>jakarta</replaceValue>
                <recursive>true</recursive>
                <fileMask>.java</fileMask>
            </configuration>
        </execution>
    </executions>
</plugin>

If you want to use the Tomcat annotation instead, adapt the <findRegex> and <replaceValue> configurations to your needs.

hth

[trajano]

Please ensure that this is not a SOURCE level annotation so that Jacoco can detect it.

[bkorcsmar]

Lombok is an example of a widely used library in java. In the latest version 1.18.30 the user can configure which Generated annotation should be added, or if it should not be added at all. The default behavior is no Generated annotation is added.

Key : lombok.addJakartaGeneratedAnnotation
Type: boolean

Generate @jakarta.annotation.Generated on all generated code (default: false).

Examples:
clear lombok.addJakartaGeneratedAnnotation
lombok.addJakartaGeneratedAnnotation = [false | true]

Key : lombok.addJavaxGeneratedAnnotation
Type: boolean

Generate @javax.annotation.Generated on all generated code (default: follow lombok.addGeneratedAnnotation).

Examples:
clear lombok.addJavaxGeneratedAnnotation
lombok.addJavaxGeneratedAnnotation = [false | true]

@ejona86 as the developer could you possible consider to listen to the request of the users of the library that you are developing and make the Generated annotation configurable similar to Lombok?

[alexanderankin]

examples of how to omit the javax annotation here #10927 (comment)

[Hc747]

Please consider the solution provided in: #11215

This has been an issue since Java 9 (7 years ago) as per #3633. The above proposal is a pragmatic, optional, opt-in and low-risk solution.

[anujpradhaan]

Summary of solutions for this problem:

1. Replace the javax annotation with jakarta. Replace javax.annotation.Generated with custom gRPC annotation #9179 (comment) Useful for Spring boot 3 and if you want to keep the generated annotation.
2. Use the Javax annotation dependency. Replace javax.annotation.Generated with custom gRPC annotation #9179 (comment).
3. We can ignore the Generated annotation all together. We can pass a configuration parameter to the plugin. Explained implement ability to skip generation of javax annotation #10927 (comment) and implement ability to skip generation of javax annotation #10927 (comment).

We ended up choosing the 3rd solution as we didn't want a javax dependency in our Spring boot 3 project.

<plugin>
        <groupId>org.xolstice.maven.plugins</groupId>
        <artifactId>protobuf-maven-plugin</artifactId>
        <version>0.6.1</version>
        <configuration>
          <protocArtifact>com.google.protobuf:protoc:3.25.3:exe:${os.detected.classifier}</protocArtifact>
          <pluginId>grpc-java</pluginId>
          <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.64.0:exe:${os.detected.classifier}</pluginArtifact>
        </configuration>
        <executions>
          <execution>
            <configuration>
              <pluginParameter>
                @generated=omit
              </pluginParameter>
            </configuration>
            <goals>
              <goal>compile</goal>
              <goal>compile-custom</goal>
            </goals>
          </execution>
        </executions>
      </plugin>

Was our config change in Maven pom.

#9179 is an open issue about replacing the javax, jakarta annotation with some custom one.

[stickfigure]

I'd just like to respond to the question of "what's the harm of having javax.annotations on the classpath?"

I have a million and a half lines of Java. I have dozens of engineers of various levels of professional development, including interns. If someone autocompletes PostConstruct and gets the wrong import, the method doesn't get called. Maybe it gets caught by tests, maybe it gets caught in review, maybe it introduces a serious bug. Putting nonfunctional javax.annotations on the classpath is dangerous.

[trajano]

Considering how old this is, I wonder if there's a fork that already the functionality that we all can jump onto.