Need some help understanding why some parts of my coding challenge answer are what they are?!

So, with this challenge I managed to get most of the skeleton down correctly (at first I was thrown by creating a method which returns a map, whilst also declaring the hashMap inside of the method!).

Here's the answer that worked: public Map<String, Integer> getCategoryCounts() { Map<String, Integer> categoryCounts = new HashMap<String, Integer>();

  for (BlogPost post : mPosts) {
    String category = post.getCategory();
    Integer count = categoryCounts.get(category);
    if (count == null) {
     count = 0; 
    }
    count ++;
    categoryCounts.put(category, count);
  }

return categoryCounts; }

A few of the finer details were lost on me however: 1)String category = post.getCategory(); Can this be declared outside of the for-loop? Also why is the method of getCategory() referring to post, rather than BlogPost? Especially as it is the class BlogPost that contains this getter for category?

2)for (BlogPost post : mPosts) Just to get this straight in my head: this is saying that for every post of type BlogPost (object) within the list of posts (mPosts)......we should etc etc? Am I saying that the right way round?

3) Integer count = categoryCounts.get(category); Like during the class tutorial, this line plus the accompanying if block is basically defining what the count is. If no count exists for a particular category, then one is begun at 0 for it. Regardless we then increment the count for that category. Finally the categoryCounts is ammended accordingly. Correct?

Finally the part .get(category) is referring to the map, so is this essentially searching for the particular category (key from the map)?