Exception in thread "main" java.lang.NoClassDefFoundError: com/google/protobuf/MessageOrBuilder

Schema Registry
1

Hi there,
I am trying out the schema registry with protobuf as in this example.

However, when I run this java -cp target/getting-started-with-ccloud-1.0.jar io.confluent.cloud.demo.ProducerApp, I got the following error message.

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/protobuf/MessageOrBuilder

Any quick pointer what is the issue?
Thanks,
xsqian

2

Seems like in the generated code it want to register all the extensions, but those can’t be found on the class path, demo-scene/SensorReadingImpl.java at 375212d7b5fe07609e70990c6ee6b91e2433f37f · confluentinc/demo-scene · GitHub.
You want https://github.com/protocolbuffers/protobuf/blob/15add1af49f13d1661d3910d0eb6697b415a19d1/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.Java among others on the classpath.
You can do this by adding

<dependency>
  <groupId>com.google.protobuf</groupId>
  <artifactId>protobuf-java</artifactId>
  <version>3.19.4</version>
  <type>bundle</type>
</dependency>

to the maven dependencies in the pom file.

3

@gklijs Thank you for the answer. I actually running into another issue: (even with -U)

(base) xsqian@[21:55:10]<getting-started-with-ccloud-java>% mvn -U clean package
[INFO] Scanning for projects...
[INFO] 
[INFO] --------< io.confluent.cloud.demo:getting-started-with-ccloud >---------
[INFO] Building getting-started-with-ccloud 1.0
[INFO] --------------------------------[ jar ]---------------------------------
Downloading from confluent: https://packages.confluent.io/maven/com/google/protobuf/protobuf-java/3.19.4/protobuf-java-3.19.4.bundle
Downloading from central: https://repo.maven.apache.org/maven2/com/google/protobuf/protobuf-java/3.19.4/protobuf-java-3.19.4.bundle
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  1.299 s
[INFO] Finished at: 2022-01-29T21:55:15-08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project getting-started-with-ccloud: Could not resolve dependencies for project io.confluent.cloud.demo:getting-started-with-ccloud:jar:1.0: Could not find artifact com.google.protobuf:protobuf-java:bundle:3.19.4 in confluent (https://packages.confluent.io/maven/) -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
(base) xsqian@[21:55:15]<getting-started-with-ccloud-java>%
4

Since you already have the Confluent repo in the repositories section, it will nu longer look in Maven Central, the default. So you need to add

<repository>
      <id>maven-central</id>
      <name>Maven central</name>
      <url>https://repo1.maven.org/maven2/</url>
</repository>

To the repositories section.