异常处理系列：Android开发问题：Failed to install Hello.apk on device 'emulator-5554!

可能是因为加载的.class文件过多的原因，导致了超出了链接时间

Window -> Preferences -> Android->DDMS ->ADB connection time out .修改成大一点如10000

Try changing the ADB connection timeout. I think it defaults that to 5000ms and I changed mine to 10000ms to get rid of that problem. If you are in Eclipse, you can do this by going through Window -> Preferences and then it is in DDMS under Android.