具体命令与错误
$ git fetch upstream fatal: 'upstream' does not appear to be a git repository fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists.
原因
你是fork的库。而源已经改变了。
解决办法
加上源库
$ git remote add upstream https://github.com/openjdk/jdk8u $ git fetch upstream