Can't get Debug, Verbose log on Nougat

My Device: Sony Xperia XA1 Nougat(7.0)

I want to show a log on Android Monitor like this:

public static final String  TAG   = MainActivity.class.getSimpleName();
public static final boolean DEBUG = true;

if(DEBUG) Log.d(TAG, "onResume()");

But..when I open the monitor window, I can't see this log even the log level is Verbose/Debug. I only can see I/W/E level on Android Monitor, and it always show:

I/art: Enter while loop...

Is it a security issue?

Thank you very much!