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javaapache-kafkagradlew

How do you prepend paths to a java class?

I'm building an older kafka (0.8.2.2) and am getting runtime errors about a missing java class:

java.lang.NoClassDefFoundError: org/apache/kafka/common/KafkaException

When I look in libs/kafka_2.10-0.8.2.2.jar, I see the existence of kafka/common/KafkaException:

$ jar tf $CLASSPATH  | grep KafkaException
kafka/common/KafkaException.class

So it appears that the build (gradlew jar) constructed the class with the org/apache missing at the start of the class path. How do I fix the path?

Solution

  • You can't prepend paths to a Java class. The path must correspond to the package name. In your case the class kafka.common.KafkaException is found in libs/kafka_2.10-0.8.2.2.jar and org.apache.kafka.common.KafkaException is found in libs/kafka-clients-0.8.2.2.jar.

    You must include libs/kafka-clients-0.8.2.2.jar in your classpath as well.