There are following difference between ArrayList and Hashtable :- 
- A hashtable store data as name, value pair. While an ArrayList only value is store.
 
- If you want to access value from the hashtable, you need to pass name. While in arraylist to access value, you need to pass index value.
 
- In a hastable you can store different type of data like int, string etc. While in arraylist you can store only similar type of data.