运行程序出现如下错误：
The connection to adb is down, and a severe error has occured.
You must restart adb and Eclipse.
Please ensure that adb is correctly located at ‘D:\java\sdk\platform-tools\adb.exe‘
此情况是其他进程监听了abd端口(5037)，而不是adb。
解决方法：进入dos窗口，输入：netstat -aon|findstr "5037"，就会出现占用的进程的PID，然后启动任务管理器，找到此PID，然后结束进程，重启eclipse即可。
原文：http://blog.csdn.net/crescent__moon/article/details/22894631