Java HashMap v/s HashTable

Map v/s Table

HashMap always brings innumerable interview questions along with itself. One of the common interview questions is the difference and similarities between Java HashMap and HashTable. You might not get the direct question like this but something on similar lines. 

We have tried to list the difference and similarity. Have a go!

Differences
S No.	HashMap	HashTable
1	Not synchronized. Not thread safe	Synchronized. Thread safe
2	Allows one Null Key and multiple null values	Null keys and Null values not allowed
3	Iterated by using Iterator	Iterated by using Enumerator
4	Iterator in HashMap is fail-fast	Enumerator in HashTable is not fail fast
5	Faster and uses less memory as unsynchronized	Slower and uses more memory as synchronized

Similarities
S No.	HashMap	HashTable
1	Does not guarantee order of Map	Does not guarantee order of Map
2	Constant Time for put/get	Constant Time for put/get
3	Works on Hashing Principle	Works on Hashing Principle
4	Implements Map Interface	Implements Map Interface