Within the larger subject of java, it is definitely going to be worth taking the time to understand the difference between hashtable and hashamp. While there are numerous differences, you will find that these items are pretty straightforward.
Furthermore, you are going to find that when it comes to these hashtable and hashmap differences, everything really comes down to one crucial fact. From this one crucial fact, everything else is going to become much easier to comprehend.
What Are The Differences Between Hashtable And Hashmap
When it comes to hashtable and hashmap, you are dealing in data structure that comes from not only hashing, but from the implementation of map interface, as well. However, there are some major differences between these concepts that you need to keep in mind.
As we mentioned before, there is a significant difference between hashtable and hashmap that can serve as your foundation for understanding everything else. This involves understand that while a hashtable is thread-safe, a hashmap is not in fact thread-safe. From this basic fact, everything else should begin to make sense. Unless you are willing to utilize external synchronizations, you will not be able to use a hashmap in conjunction with a multi-thread java application. In other words, if you want to use a multi-thread application, you are going to have to turn to a hashtable.
Null keys and null values is another aspect to this subject. One null key is allowed with a hashmap, along with any number of null values. When it comes to a hashtable, you are talking about something that doesn’t allow for a null key or null value in your hashtable object.
In terms of iterating the values, you should note that a hashmap object value is iterated through the use of an iterator. Beyond vectors, a hashtable is the only class that utilizes enumerators for the iteration of the values of hashtable objects.
Performance is probably the category you want to pay the most attention to, in terms of understanding the differences between hashtable and hashmap. You are going to find that not only is the hashmap faster, but that it is also going to use a lot less memory than the hashtable. This is largely because of the fact that more often than not, an unsynchronized object is going to offer a considerably superior performance, when compared to the performance of a synchronized object.
These are the main differences, but there are a few others worth exploring.
