How to add the function of gRPC client to existed Micronaut http microservices

Environment:

• Micronaut version: 4.6.3
• JDK: 17

I have a rest api developed with Micronaut. Now I want to add the feature of gRPC client to this rest api for calling a gRPC server at http://localhost:50051. I have read https://micronaut-projects.github.io/micronaut-grpc/latest/guide/index.html but there are still some information not described clearly. Following the suggestion of chatgpt, I add some lines and blocks to my current build.gradle

build.gradle

plugins {
    id("groovy")
    id("com.github.johnrengelman.shadow") version "8.1.1"
    id("io.micronaut.application") version "4.4.2"
    id("io.micronaut.aot") version "4.4.2"
    id("com.google.protobuf") version "0.9.2" // I add this line
}

version = "0.1"
group = "com.example"

repositories {
    mavenCentral()
}

dependencies {
    annotationProcessor("org.projectlombok:lombok")
    annotationProcessor("io.micronaut:micronaut-http-validation")
    annotationProcessor("io.micronaut.serde:micronaut-serde-processor")
    implementation("io.micronaut:micronaut-http-client")
    implementation("io.micronaut.serde:micronaut-serde-jackson")
    implementation("jakarta.annotation:jakarta.annotation-api")  // I add this line
    compileOnly("org.projectlombok:lombok")
    runtimeOnly("ch.qos.logback:logback-classic")
    runtimeOnly("org.yaml:snakeyaml")

    // I add below 2 lines
    implementation("io.micronaut.grpc:micronaut-grpc-runtime")
    implementation("io.micronaut.grpc:micronaut-grpc-client-runtime")
}


application {
    mainClass = "com.example.Application"
}
java {
    sourceCompatibility = JavaVersion.toVersion("17")
    targetCompatibility = JavaVersion.toVersion("17")
}


graalvmNative.toolchainDetection = false

micronaut {
    runtime("netty")
    testRuntime("spock2")
    processing {
        incremental(true)
        annotations("com.example.*")
    }
    aot {
        // Please review carefully the optimizations enabled below
        // Check https://micronaut-projects.github.io/micronaut-aot/latest/guide/ for more details
        optimizeServiceLoading = false
        convertYamlToJava = false
        precomputeOperations = true
        cacheEnvironment = true
        optimizeClassLoading = true
        deduceEnvironment = true
        optimizeNetty = true
        replaceLogbackXml = true
    }
}


// I add below protobuf block
protobuf {
    protoc { artifact = "com.google.protobuf:protoc:3.25.5" }
    plugins {
        grpc { artifact = "io.grpc:protoc-gen-grpc-java:1.66.0" }
    }
    generateProtoTasks {
        all()*.plugins {grpc {}}
    }
}

// I add below sourceSets block
sourceSets {
    main {
        java {
            srcDirs 'build/generated/source/proto/main/grpc'
            srcDirs 'build/generated/source/proto/main/java'
        }
    }
}

application.yml

micronaut:
  application:
    name: grpc-http-client-example
  server:
    port: 8080


## I add below grpc block
grpc:
  channels:
    greeter:
      address: 'http://localhost:50051'
      plaintext: true

Also, I add a .proto file proviede by the gRPC-server as below to src/main/proto

grpc-server-example.proto

syntax = "proto3";

option java_multiple_files = true;
option java_package = "com.example";
option java_outer_classname = "HelloWorldProto";
option objc_class_prefix = "HLW";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

Now I execute below command:

  ./gradlew clean generateProto
  ./gradlew run

Then it appears below error:

9:23:57 a.m.: Executing ':classes'...

> Task :extractIncludeProto UP-TO-DATE
> Task :extractProto UP-TO-DATE
> Task :generateProto UP-TO-DATE

> Task :compileJava FAILED

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

For more on this, please refer to https://docs.gradle.org/8.8/userguide/command_line_interface.html#sec:command_line_warnings in the Gradle documentation.
4 actionable tasks: 1 executed, 3 up-to-date
E:\Project-Space\microservices\grpc-http-client2-example\build\generated\source\proto\main\grpc\com\example\GreeterGrpc.java:10: error: cannot find symbol
@javax.annotation.Generated(
                 ^
  symbol:   class Generated
  location: package javax.annotation
1 error

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.

Below is the directory structure of the rest api project

How to fix the error?