问题汇总：An internal error occurred during: "Launching Appium_demo"
An internal error occurred during: "Launching Appium_demo".
java.lang.NullPointerException
问题产生原因是:缺少Java development tools .
解决办法：安装之后就OK了。
安装方法：打开eclipse-->help-->install new software输入//download.eclipse.org/releases/juno ，
在Programing language下找到eclipse java development tools
