If you don’t have a huge list of strings the shortest way to implement it is by using Collections.frequency
method, like this:
List<String> list = new ArrayList<String>();
list.add("aaa");
list.add("bbb");
list.add("aaa");
Set<String> unique = new HashSet<String>(list);
for (String key : unique) {
System.out.println(key + ": " + Collections.frequency(list, key));
}
Output:
aaa: 2
bbb: 1