Jdk_switcher: command not found

#1

As the issue described, I added source ~/.jdk_switcher_rc or source /opt/jdk_switcher/jdk_switcher.sh in my Travis yml,but it shows that there’s no such file, here is my project: https://github.com/apache/rocketmq,
and it’s the travis detail: https://travis-ci.org/apache/rocketmq/builds/529579187?utm_source=github_status&utm_medium=notification

Please help me