Android : Android compare two HashMap Integer and String

I got two HashMaps with Strings and Integers and both of them carry "20" and 20 When i'm trying to compare them using toString() i always get inequality:

HashMap<String, String> vals = HashMap<String, String>();
HashMap<Integer, Integer> nums = HashMap<Integer, Integer>();

if(nums.get(id).toString() == vals.get("num")) {
    Log.i(TAG, "DataBase.updateOrder(): number is the same");
} else {
    Log.i(TAG, "DataBase.updateOrder(): number has changed");
}

When i use Integer.valueOf() for String HashMap it works well and they are equal:

if(nums.get(id) == Integer.valueOf(vals.get("num")))

And of course the following record doens't work at all in the way i need:

num.get(id).equals(vals.get("num"))

So the question is why does my first bit of code not work (as i expected)?