kafka java.rmi.server.ExportException: Port already in use

当你在kafka-run-class.sh中添加了export JMX_PORT=9300 开启了 jmx 后, 在使用 kafka bin/目录下的脚本时会报如下错误:

java.rmi.server.ExportException: Port already in use

可参考如下文章解决 https://github.com/apache/kafka/pull/1983/commits/2c5d40e946bcc149b1a9b2c01eced4ae47a734c5