Linux下运行Java项目时，出现No X11 DISPLAY variable was set, but this program performed an operation which requires it.的问题解决

在~/.bashrc环境变量文件最下方加入：

export DISPLAY=:0.0

然后，刷新环境变量以使其生效：

source ～/.bashrc

参考：http://stackoverflow.com/questions/662421/no-x11-display-variable-what-does-it-mean