### Question:
HMapKI implements MapKI<K>, Cloneable, Serializable { @Override public long dot(MapKI<K> m) { int s = 0; for (MapKI.Entry<K> e : m.entrySet()) { K key = e.getKey(); if (this.containsKey(key)) { s += this.get(key) * e.getValue(); } } return s; } @SuppressWarnings("unchecked")  HMapKI(int initialCapacity, float loadFactor);  HMapKI(int initialCapacity); @SuppressWarnings("unchecked")  HMapKI();  HMapKI(MapKI<? extends K> m); @Override int size(); @Override boolean isEmpty(); @Override int get(K key); @Override boolean containsKey(K key); @Override int put(K key, int value); @Override void putAll(MapKI<? extends K> m); @Override int remove(K key); @Override void clear(); @Override boolean containsValue(int value); @SuppressWarnings("unchecked") @Override Object clone(); @Override Set<K> keySet(); @Override Collection<Integer> values(); @Override Set<MapKI.Entry<K>> entrySet(); @Override String toString(); @Override void plus(MapKI<K> m); @Override long dot(MapKI<K> m); @Override void increment(K key); @Override void increment(K key, int value); @SuppressWarnings("unchecked") MapKI.Entry<K>[] getEntriesSortedByValue(); MapKI.Entry<K>[] getEntriesSortedByValue(int n); @SuppressWarnings("unchecked") MapKI.Entry<K>[] getEntriesSortedByKey(); MapKI.Entry<K>[] getEntriesSortedByKey(int n);  }### Answer:
@Test public void testDot() throws IOException { HMapKI<Text> m1 = new HMapKI<Text>(); m1.put(new Text("hi"), 5); m1.put(new Text("there"), 2); m1.put(new Text("empty"), 3); HMapKI<Text> m2 = new HMapKI<Text>(); m2.put(new Text("hi"), 4); m2.put(new Text("there"), 4); m2.put(new Text("test"), 5); assertEquals(28, m1.dot(m2)); }