Question

i have question about how to count matched elements in ArrayList in java..
Ex: My ArrayList contain [sport, sport, ball , player, sport]

i need to output like:

word sport frequency 3
word ball  frequency 1
word player frequency 1

thanks for advance

Answer 1

Use a Map:

Map<String, Integer> occurrencies = new HashMap<String, Integer>();
for (String word : list) {
    occurrencies.put(word, occurrencies.containsKey(word)
    ? occurrencies.get(word) + 1 : 1);
}
for (Entry<String, Integer> entry : occurrencies.entrySet()) {
    System.out.println("Word: "+entry.getKey()
                     + ", occurences: "+entry.getValue());
}

If you want the words to be sorted alphabetically, use TreeMap instead of HashMap.

(Of course this would be much easier using a Guava Multiset as others have suggested)