以编程方式设置Android的日期/时间

我需要以编程方式从Android设置日期/时间，但没有成功！我上面有这三个来源：

源代码1

AlarmManager alarm = (AlarmManager) getSystemService(ALARM_SERVICE);  
alarm.setTime(1330082817000); 

AndroidManifest：

<uses-permission android:name="android.permission.SET_TIME" />  
<uses-permission android:name="android.permission.SET_TIME_ZONE" />  

例外：

Service fatal error : Unable to start activity ComponentInfo{br.com.tdta.service/br.com.tdta.service.Service}: java.lang.SecurityException: setTime: Neither user 10038 nor current process has android.permission.SET_TIME.  
java.lang.RuntimeException: Unable to start activity ComponentInfo{br.com.tdta.service/br.com.tdta.service.Service}: java.lang.SecurityException: setTime: Neither user 10038 nor current process has android.permission.SET_TIME.  
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)  
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)  
    at android.app.ActivityThread.access$2300(ActivityThread.java:125)  
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)  
    at android.os.Handler.dispatchMessage(Handler.java:99)  
    at android.os.Looper.loop(Looper.java:123)  
    at android.app.ActivityThread.main(ActivityThread.java:4627)  
    at java.lang.reflect.Method.invokeNative(Native Method)  
    at java.lang.reflect.Method.invoke(Method.java:521)  
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)  
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)  
    at dalvik.system.NativeStart.main(Native Method)  
Caused by: java.lang.SecurityException: setTime: Neither user 10038 nor current process has android.permission.SET_TIME.  
    at android.os.Parcel.readException(Parcel.java:1247)  
    at android.os.Parcel.readException(Parcel.java:1235)  
    at android.app.IAlarmManager$Stub$Proxy.setTime(IAlarmManager.java:237)  
    at android.app.AlarmManager.setTime(AlarmManager.java:289)  
    at br.com.tdta.service.Service.onCreate(Service.java:32)  
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)  
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)  
... 11 more  

====

源代码2

boolean itsWork = SystemClock.setCurrentTimeMillis(1330082817000);  
System.out.println(itsWork);  

表现：

<uses-permission android:name="android.permission.SET_TIME" />  
<uses-permission android:name="android.permission.SET_TIME_ZONE" />  

其工作价值：

false  

====

源代码3

SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd.hhmmss");
String data = format.format(new Date(1330082817000));
try {
    Runtime.getRuntime().exec("date -s " + data);
} catch (IOException e) {
}

我究竟做错了什么？

提前致谢！