Looking at the code specifically line 393, it looks like different hashes have been mapped to same index. I had an understanding that the hashcode is used to determine what
The answer is surprisingly YES. I put Sysout's in the code of put() to observe it's behaviour
public V put(K key, V value) {
if (table == EMPTY_TABLE) {
System.out.println("Put: Table empty. Inflating table to threshold:" + threshold);
inflateTable(threshold);
}
if (key == null)
return putForNullKey(value);
int hash = hash(key);
System.out.println("Put: Key not null:" + hash);
int i = indexFor(hash, table.length);
System.out.println("Put: Obtained index:" + i);
for (Entry e = table[i]; e != null; e = e.next) {
System.out.println("Put: Iteraing over table[" + i + "] elements");
Object k;
System.out.println("Put: Checking if hash & key are equal");
if (e.hash == hash && ((k = e.key) == key || key.equals(k))) {
V oldValue = e.value;
e.value = value;
e.recordAccess(this);
return oldValue;
}
}
System.out.println("Put: Incrementing modCounter");
modCount++;
System.out.println("Put: Adding a new Entry[hash="
+ hash + ", key=" + key + ", value="
+ value + ", i=" + i + "]");
addEntry(hash, key, value, i);
return null;
}
And then tested with the following inputs,
MyHashMap p = new MyHashMap<>();
p.put(0, "Z");
p.put(1, "A");
p.put(17, "A");
And guess what the output comes
Put: Table empty. Inflating table to threshold:16
Inflate: RoundUpPowerOf2 of size=16
Inflate: Setting Min of [capacity * loadFactor, MAXIMUM_CAPACITY + 1] as threshold
Inflate: Given values[capacity=16, loadfactor=0.75, MAXIMUM_CAPACITY=1073741824
Creating array of Entry[] with size:16
Put: Key not null:0
IndexFor: calculating index for [given hash=0, length=16]
Put: Obtained index:0
Put: Incrementing modCounter
Put: Adding a new Entry[hash=0, key=0, value=Z, i=0]
Put: Key not null:1
IndexFor: calculating index for [given hash=1, length=16]
Put: Obtained index:1
Put: Incrementing modCounter
Put: Adding a new Entry[hash=1, key=1, value=A, i=1]
Put: Key not null:16
IndexFor: calculating index for [given hash=16, length=16]
Put: Obtained index:0
Put: Iteraing over table[0] elements
Put: Incrementing modCounter
Put: Adding a new Entry[hash=16, key=17, value=A, i=0]
So, as you can see, two entries got stored in the same index. Was very excited to see such behaviour. Inquisitively trying to get an answer for this.