Android :: Sharing Global Variables Across Activities - Problem When Using Webview

I'm sharing some variables accross activities by using a class like this :

CODE:..........

Then I'm using these variables anywhere across my multiple activites with ...if (Globals.hint2_stockview_valuation == false) {....}

Pretty basic and it was working fine untill ...

I introduced some webview stuff like this:

CODE:...........

And here's the News_Webview.class:

CODE:............

The problem now is that, when it "comes back" from this Activity, it looks like my Globals variables have disappeared ?

if (Globals.hint2_stockview_valuation == false) {

fires an error :

06-23 12:14:03.443:
ERROR/AndroidRuntime(2611): Caused by:
java.lang.NullPointerException

2 Questions then:

Should I use something else than this "Global" class to share variables across activities ? Is it just bad practice to do this ?? I know that I can use the preferences but I thought it was quicker to do it this way (no need to "read" the preferences everytime I start a new activity ...Should I "get back" my savedInstanceState in some way when my activity returns from the News_Webview.class ?