java.lang.NoClassDefFoundError: org/apache/kafka/connect/errors/ConnectException on Secret Provider check in ensure script

[pkleindl]

Hi
I was trying to use the secret provider for Azure Key Vault from lenses.io
https://github.com/lensesio/secret-provider
https://github.com/lensesio/secret-provider/releases/tag/2.1.6

I added the jar file to the directory used
COPY secret-provider-2.1.6-all.jar /usr/share/java/cp-base-new/

When I start the container (confluentinc/cp-kafka-connect-base:latest) I get the following exception:

===> Check if Kafka is healthy ...
Using log4j config /etc/cp-base-new/log4j.properties
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/kafka/connect/errors/ConnectException
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Class.java:398)
        at org.apache.kafka.common.utils.Utils.loadClass(Utils.java:419)
        at org.apache.kafka.common.utils.Utils.newInstance(Utils.java:408)
        at org.apache.kafka.common.config.AbstractConfig.instantiateConfigProviders(AbstractConfig.java:577)
        at org.apache.kafka.common.config.AbstractConfig.resolveConfigVariables(AbstractConfig.java:521)
        at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:112)
        at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:146)
        at org.apache.kafka.clients.admin.AdminClientConfig.<init>(AdminClientConfig.java:235)
        at org.apache.kafka.clients.admin.Admin.create(Admin.java:144)
        at org.apache.kafka.clients.admin.AdminClient.create(AdminClient.java:49)
        at io.confluent.admin.utils.ClusterStatus.isKafkaReady(ClusterStatus.java:136)
        at io.confluent.admin.utils.cli.KafkaReadyCommand.main(KafkaReadyCommand.java:149)
Caused by: java.lang.ClassNotFoundException: org.apache.kafka.connect.errors.ConnectException
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
        ... 13 more

When I add connect-api-3.4.0.jar to the directory this exception does not occur.

Maybe this class was moved in the past, would probably be good to include the file by default.