Three dots in ActionBar does not appear.

This is an awful hack that breaks consistency with the rest of the apps on the platform, but its works. Put this code in onCreate() method of MainActivity.java after setContentView(R.layout.activity_main);

try {
            ViewConfiguration config = ViewConfiguration.get(this);
            Field menuKeyField = ViewConfiguration.class.getDeclaredField("sHasPermanentMenuKey");
            if(menuKeyField != null) {
                menuKeyField.setAccessible(true);
                menuKeyField.setBoolean(config, false);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

I got the answer and it was what everyone repeatedly says: With the device that has physical menu button, overflow does not appear. I literally never use this button since,,, come on, who uses for what? Sorry, but at least for me, it is useless button. And this way I didn't realize my device has it. Besides, Twitter app or Facebook app has overflow so I thought this device is "the one that can display it". Maybe those apps has got another way to achieve it.