Add new file

02/MostCommonWord.java

+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.*;
+
+public class MostCommonWord {
+    private static final String BOOK_FILENAME = "alice.txt";
+
+    public static void main(String[] args) throws FileNotFoundException {
+        // NOTE: This is wrong...do not copy.
+        // keys are words
+        // values are number of times that word occurs
+        Map<String, Integer> map = new HashMap<>();
+        Scanner s = new Scanner(new File(BOOK_FILENAME));
+        while (s.hasNext()) {
+            String next = s.next();
+            if (!map.containsKey(next)) {
+                map.put(next, 0);
+            }
+            int oldValue = map.get(next);
+            map.put(next, oldValue + 1);
+            // map.get(next) = map.get(next) + 1
+        }
+        // print size of map
+        String best = "???";
+        for (String key : map.keySet()) {
+            if (map.get(best) == null || map.get(key) > map.get(best)) {
+               best = key;
+            }
+            // ... implement together
+        }
+        System.out.println(best);
+    }
+}