Android in the connection to ADB are down, problems and solutions

Self-summary of the problems and methods that often appear in Android that are not solved

1. Error:
BUILD FAILED
D:\workspace\ganji\build.xml:144:the following error occurred while executing the line:
d:\workspace\ganji\build.xml:271:unable to delete file D:\workspace\ganji\tmp\proguard\tmp.jar
Solve:
A simulator has been opened and cannot be recompiled and must be closed. For Ant


2. Error:
The connection to ADB are down, and a severe error has occured.
Who can solve this problem?
Solve:
CMD jumps to the SDK tools file path
ADB kill-server
and then ADB start-server

3. Error:
The connection to ADB are down, and a severe error has occured.
[2010-03-11 09:36:56-helloopone] You must restart ADB and Eclipse.
[2010-03-11 09:36:56-helloopone] Please ensure this adb is correctly located at ' D:\OPhoneSDK_1.5 \platform-tools\adb.exe ' and can be executed.
Solve:
Method 1.cmd in ADB kill-server, and then Adb-startserver
Method 2. Method 1 doesn't work, kill Adb.exe in Task Manager, and then restart Eclipse.
Method 3. Methods 1 and 2 do not work, then look at the last sentence of the error: Platform-tools Adb.exe (my error is that there is no Platform-tools folder under the relevant path, so I chose to create a new folder, and copy all of the files in tools to Platform-tools)

Android in the connection to ADB are down, problems and solutions