在android5.0上运行 Runtime.getRuntime("am start -n com.android.settings/.Settings") 时，抛出异常：
D/AndroidRuntime( 8331): Calling main entry com.android.commands.am.Am
W/ActivityManager( 750): Permission Denial: startActivity asks to run as user -2 but is calling from user 0; this requires android.permission.INTERACT_ACROSS_USERS_FULL
这是因为5.0手机是多用户，adb shell am 的用户是su和程序的用户不是同一个，解决方案：
add --user 0 option to your am command.
The "user" in the command-line refers to Jelly Bean's user profiles, not to Unix user IDs. When you're using a terminal session, you need to specify which user profile the app should be running in.
参考
http://android.stackexchange.com/questions/54140/running-am-commands-in-terminal-without-using-su