Type Inference

• Let the compiler guess the types

• Saves a miniscule amount of typing; is it easier to read?

•   // print a frequency table of words
    public static void main(String[] args) {
       HashMap<String, Integer> map = new HashMap<String, Integer>();
      for(word : args) {
        int freq := map.get(word); // autoboxing
        map.put(word, (freq==null) ? 1 : freq+1);
      }
      System.out.println(map);
    }

  becomes

    // print a frequency table of words
    public static void main(String[] args) {
      map := new HashMap<String, Integer>();
      for(word : args) {
        freq := map.get(word);
        map.put(word, (freq==null) ? 1 : freq+1);
      }
      System.out.println(map);
    }

  or

    public static void main(String[] args) {
      final map = new HashMap<String, Integer>();
      for(final word : args) {
        final freq=map.get(word);
        map.put(word, (freq==null) ? 1 : freq+1);
      }
      System.out.println(map);
    }

• However it's final in both cases.

• Locked to the concrete class