how to find frequency of each word in string in java

1HOW TO COUNT OCCURRENCE OF THE WORDS IN STRING 
2(It can also be solved by using nested for loops...)
3
4String str = "I am happy and why not and why are you not happy you should be";
5   String [] arr = str.split(" ");
6   Map<String, Integer> map = new HashMap<>();
7
8   for (int i=0 ; i < arr.length ; i++){
9       if (!map.containsKey(arr[i])){
10            map.put(arr[i],1);
11           } else{
12         map.put(arr[i],map.get(arr[i])+1);
13        }
14        }
15     for(Map.Entry<String, Integer> each : map.entrySet()){
16
17    System.out.println(each.getKey()+" occures " + each.getValue() + " times");
18    }