Debug logging does not work with JavaExec task

I’m not getting any debug logging (from Gradle) to the terminal when running a JavaExec task. Is there a way to fix this?

$ gradle -d -q producer < ../hadoop/src/main/resources/occupancy.json
 Exception in thread "main" java.lang.IllegalArgumentException: requirement failed: Missing required property 'metadata.broker.list'
 at scala.Predef$.require(Predef.scala:145)
 at kafka.utils.VerifiableProperties.getString(VerifiableProperties.scala:158)
 at kafka.producer.ProducerConfig.<init>(ProducerConfig.scala:66)
 at kafka.producer.ProducerConfig.<init>(ProducerConfig.scala:56)
 at com.parc.hpa.kafka_test.ExampleProducer.<init>(ExampleProducer.java:18)
 at com.parc.hpa.kafka_test.ExampleProducerClient.main(ExampleProducerClient.java:11)