I am trying to setup a mongo-kafka-connector against Apache Kafka 2.5. I am using Kafka-protobuff-connector.

ExchangeMessage.proto -------------------- syntax = "proto3"; package exchange_message_def;  option java_package = "kafka.message"; option java_outer_classname = "ExchangeMessage"; option optimize_for = SPEED;  message Order {   string oid = 1; } 

I built a jar file for this proto and placed within plugins path. But I am getting following error.

My Pom file:

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>      <groupId>com.data</groupId>     <artifactId>data-exchange</artifactId>     <version>0.0.1-SNAPSHOT</version>     <packaging>jar</packaging>      <properties>         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>         <skip.tests>false</skip.tests>     </properties>      <dependencies>         <!-- Unit testing -->         <dependency>             <groupId>junit</groupId>             <artifactId>junit</artifactId>             <version>4.12</version>             <scope>test</scope>         </dependency>         <!-- Protocol Buffers -->         <dependency>             <groupId>com.google.protobuf</groupId>             <artifactId>protobuf-java</artifactId>             <version>3.12.2</version>         </dependency>         <dependency>             <groupId>com.github.os72</groupId>             <artifactId>protoc-jar-maven-plugin</artifactId>             <version>3.11.4</version>         </dependency>         <dependency>             <groupId>io.grpc</groupId>             <artifactId>protoc-gen-grpc-java</artifactId>             <version>1.30.2</version>             <type>pom</type>         </dependency>     </dependencies>     <build>         <plugins>             <plugin>                 <groupId>org.apache.maven.plugins</groupId>                 <artifactId>maven-compiler-plugin</artifactId>                 <configuration>                     <source>11</source>                     <target>11</target>                 </configuration>             </plugin>             <plugin>                 <groupId>org.apache.maven.plugins</groupId>                 <artifactId>maven-jar-plugin</artifactId>                 <version>3.0.2</version>                 <configuration>                     <finalName>${project.name}-${project.version}</finalName>                     <archive>                         <manifest>                             <addClasspath>true</addClasspath>                             <classpathPrefix>lib/</classpathPrefix>                         </manifest>                     </archive>                 </configuration>             </plugin>             <plugin>                 <artifactId>maven-assembly-plugin</artifactId>                 <version>2.5.5</version>                 <configuration>                     <appendAssemblyId>false</appendAssemblyId>                     <finalName>${project.name}-${project.version}</finalName>                     <descriptors>                         <descriptor>src/assembly/dist.xml</descriptor>                     </descriptors>                 </configuration>             </plugin>             <plugin>                 <artifactId>maven-dependency-plugin</artifactId>                 <executions>                     <execution>                         <phase>process-sources</phase>                         <goals>                             <goal>copy-dependencies</goal>                         </goals>                         <configuration>                             <outputDirectory>${project.build.directory}/lib</outputDirectory>                         </configuration>                     </execution>                 </executions>             </plugin>             <plugin>                 <groupId>com.github.os72</groupId>                 <artifactId>protoc-jar-maven-plugin</artifactId>                 <version>3.11.4</version>                 <executions>                     <execution>                         <phase>generate-sources</phase>                         <goals>                             <goal>run</goal>                         </goals>                         <configuration>                             <protocVersion>3.12.2</protocVersion>                             <includeDirectories>                                 <include>src/main/proto</include>                             </includeDirectories>                             <inputDirectories>                                 <include>src/main/proto</include>                             </inputDirectories>                             <outputTargets>                                 <outputTarget>                                     <type>java</type>                                     <addSources>main</addSources>                                     <outputDirectory>src/main/java</outputDirectory>                                 </outputTarget>                                 <outputTarget>                                     <type>grpc-java</type>                                     <addSources>main</addSources>                                     <outputDirectory>src/main/grpc</outputDirectory>                                     <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.30.2</pluginArtifact>                                 </outputTarget>                                 <outputTarget>                                     <type>python</type>                                     <addSources>main</addSources>                                     <outputDirectory>src/main/python</outputDirectory>                                 </outputTarget>                                 <outputTarget>                                     <type>js</type>                                     <addSources>main</addSources>                                     <outputDirectory>src/main/js</outputDirectory>                                 </outputTarget>                             </outputTargets>                         </configuration>                     </execution>                 </executions>             </plugin>         </plugins>     </build> </project> 

Mongo-Sink config :

{     "name":"mongo-sink",             "config":{     "name": "mongo-sink",     "topics": "zz",     "connector.class": "com.mongodb.kafka.connect.MongoSinkConnector",     "tasks.max":"1",     "key.converter": "org.apache.kafka.connect.converters.IntegerConverter",     "value.converter": "com.blueapron.connect.protobuf.ProtobufConverter",     "value.converter.protoClassName":"kafka.message.ExchangeMessage$Order",     "key.converter.schemas.enable":false,     "value.converter.schemas.enable":true,     "connection.uri": "mongodb://user:password@localhost:27017",     "database":"data_db",     "collection":"zz",     "max.num.retries":"3",     "retries.defer.timeout":"5000",     "key.projection.type":"none",     "key.projection.list": "",     "value.projection.type":"none",     "value.projection.list": "",     "field.renamer.mapping":"[]",     "field.renamer.regex":"[]",     "document.id.strategy":"com.mongodb.kafka.connect.sink.processor.id.strategy.BsonOidStrategy",     "post.processor.chain":"com.mongodb.kafka.connect.sink.processor.DocumentIdAdder",     "delete.on.null.values":false,     "writemodel.strategy":"com.mongodb.kafka.connect.sink.writemodel.strategy.ReplaceOneDefaultStrategy",     "max.batch.size":"2",     "rate.limiting.timeout":"100",     "rate.limiting.every.n":"100",     "change.data.capture.handler":""     } } 

I am getting following error:

org.apache.kafka.connect.errors.ConnectException: Proto class kafka.message.ExchangeMessage$Order not found in the classpath at com.blueapron.connect.protobuf.ProtobufConverter.configure(ProtobufConverter.java:48) at org.apache.kafka.connect.runtime.isolation.Plugins.newConverter(Plugins.java:293) at org.apache.kafka.connect.runtime.Worker.startTask(Worker.java:442) at org.apache.kafka.connect.runtime.distributed.DistributedHerder.startTask(DistributedHerder.java:1147) at org.apache.kafka.connect.runtime.distributed.DistributedHerder.access$1600(DistributedHerder.java:126) at org.apache.kafka.connect.runtime.distributed.DistributedHerder$12.call(DistributedHerder.java:1162) at org.apache.kafka.connect.runtime.distributed.DistributedHerder$12.call(DistributedHerder.java:1158) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at java.base/java.lang.Thread.run(Thread.java:834)