Question: I am trying to use some arguments for an Instrumentation test. I noticed that I can read system properties with `System.getProperty()` function. So I use setprop command to set a system property. For example: `adb shell setprop AP 123`.
Inside my Test code I try to read this AP property with : 

```

tmp = System.getProperty("AP"); 
Log.d("MyTest","AP Value = " + tmp);

```

Then I use logcat to view this debug message but I get a null value for this property. Any ideas on what could be wrong? 
Note that I can still read the system property with `adb shell getprop AP` command.

Answer: 
You need a root to set system property

```
adb shell
su
setprop AP 123

```
import android.os.SystemProperties

String s = SystemProterties.get("ro.xxx.xxx","default value if property not set");