Android - override font with bold-light styles

Question

Can we achieve a font override for an entire application with BOLD / LIGHT fonts?

I tried the below code and it's changing the fonts. But I'm not able to achieve bold and light font styles.

public class FontsOverride {

    public static void setDefaultFont(Context context, String staticTypefaceFieldName, String fontAssetName) {
        final Typeface regular = Typeface.createFromAsset(context.getAssets(), fontAssetName);
        replaceFont(staticTypefaceFieldName, regular);
    }

    protected static void replaceFont(String staticTypefaceFieldName,final Typeface newTypeface) {
        if (Build.VERSION.SDK_INT >= 21) {
            Map<String, Typeface> newMap = new HashMap<String, Typeface>();
            String fontStyle = staticTypefaceFieldName.toLowerCase().replace("_", "-");
            newMap.put(fontStyle, newTypeface);
            try {
                final Field staticField = Typeface.class.getDeclaredField("sSystemFontMap");
                staticField.setAccessible(true);
                staticField.set(null, newMap);
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        } else {
            try {
                final Field staticField = Typeface.class.getDeclaredField(staticTypefaceFieldName);
                staticField.setAccessible(true);
                staticField.set(null, newTypeface);
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
    }
}

And then add below code in application onCreate method..

FontsOverride.setDefaultFont(this, "SANS_SERIF", "Montserrat-Regular.ttf");

I tried with the

FontsOverride.setDefaultFont(this, "SANS_SERIF_LIGHT", "Montserrat-Light.otf");

but no luck. Is there any way we can do this?