Added fix for hash value clash because of moduls 16 reduces too often…

… to index of 4 which lead to index clashes when we didn't want them

src/main/java/datastructures/HashTable.java

@@ -70,19 +70,15 @@ public String get(String key) {
     private int getIndex(String key) {
         // Get the hash code
         int hashCode = key.hashCode();
-        System.out.println("hashCode = " + hashCode);
 
         // Convert to index
         int index = (hashCode & 0x7fffffff) % INITIAL_SIZE;
-//        int index = hashCode % INITIAL_SIZE;
 
         // Hack to force collision for testing
         if (key.equals("John Smith") || key.equals("Sandra Dee")) {
-            index = 4;
+            index = 7; // 4 clashes with other names (changed to 7)
         }
 
-        System.out.println("index = " + index);
-
         return index;
     }
 

src/test/java/datastructures/HashTableTest.java

@@ -26,10 +26,17 @@ public void PutAndGet() {
         Assert.assertEquals("521-5030", hashTable.get("Sam Doe"));
         Assert.assertEquals("521-9655", hashTable.get("Sandra Dee"));
         Assert.assertEquals("418-4165", hashTable.get("Ted Baker"));
+        Assert.assertEquals(null, hashTable.get("Tim Lee"));
 
         hashTable.toString();
     }
 
+    @Test
+    public void Empty() {
+        Assert.assertEquals(null, hashTable.get("Tim Lee"));
+        hashTable.toString();
+    }
+
     @Test
     public void Collision() {
         // these keys will collide
@@ -38,5 +45,6 @@ public void Collision() {
 
         Assert.assertEquals("521-1234", hashTable.get("John Smith"));
         Assert.assertEquals("521-9655", hashTable.get("Sandra Dee"));
+        Assert.assertEquals(null, hashTable.get("Tim Lee"));
     }
 }