No. report. * It does not allow null for both key and value. HashMap vs HashTable. 24.8k 14 14 gold badges 147 … Hashtable Hashtable is basically a data structure to retain values of key-value pair. HashMap is not thread-safe. HashMap is fast as compared to HashTable. Are you preparing for an interview for a Java profession? HashMap Vs HashTable in Java. Now, the question that arises here is that when should we use BST over Hash Table and where should we prefer Hash Table over BST? It stores key/value pair in hash table. (HashMap Here) HashMap, HashSet and HashTable: HashMap, HashSet and Hashtable usually store values in key value pair. Comparison: BST vs HashTable. You must understand the differences between HashMap and HashTable as it is an important interview question for any Java professional to kickstart the career. ** Both HashTable and HashMap implements Map interface. The HashMap and Hashtable, both are used to represent a group of objects that are represented in pair. So we have seen the differences between the Binary Search Tree and Hash Table. ; Once the size of Hashtable and SynchronizedMap becomes considerable large because for the iteration it has to be locked for the longer duration. 100% Upvoted. HashMap vs Hashtable. Hashtable. No. ThreadSafe. While in ConcurrentHashMap, even if its size become very large, only portion or segment of the Map is locked which improves the performance in multithreading environment. Yes. The collection of Entries is referred by the object of HashMap and Hashtable. Performance. Close. Vote. Posted by just now. save. HashMap vs HashSet vs Hashtable – HashSet with Examples: Collections: HashMap, HashSet and Hashtable are a part of Collections. In single threaded environment, it is much faster than Hashtable.So if you do not work in multi thread environment ,then hashMap is recommended. The basic Hashtable is quite similar to the HashMap, even down the method names. It will throw NullPointerException. Follow edited Jan 19 '15 at 11:20. naXa. Share. On the other hand, Hashtable is thread safe, and therefore can be shared between multiple threads. In Hashtable, you specify an object that can be used as a key and the value that goes with the key. HashMap is preferred over the HashTable as HashTable is a legacy class and is considered as due to depreciation. HashTable on the other hand is the legacy class and was introduced prior to HashMap. HashMap is the best thing to use in a single threaded application. share. Summary. In this article we are going to understand in detail regarding HashMap, HashSet and HashTable Each pair is called Entry object. Improve this answer. We have already discussed other popular java interview questions like ArrayList vs Vector and Comparator vs Comparable.This question is generally asked in java intereview to check whether candidate understand correct usage of collection classes and has knowledge of alternative solutions. Yes. Hashtable vs HashMap: Parameter. Log in or sign up to leave a comment Log In … hide. Synchronized. When to use which data structure? 0 comments. HashMap vs HashTable. The primary difference between HashMap and Hashtable is that HashMap is not thread-safe, and therefore cannot be shared between multiple threads without external synchronization. Keys in a collection must be unique or distinctive. HashMap. HashTable; 1: Introduction: Hashmap is the advanced version of HashTable and is introduced as a new class in JDK 1.2. I'm having trouble understanding when to use a hashmap and when to use a hashtable in java? Difference between HashMap and Hashtable is one of the most popular java interview questions. Synchronization of HashMap Vs. Hashtable; Both HashMap and Hashtable use hashing techniques to store values based on the key. Due to theadSafe and Synchronized,it is often slower than HashMap. HashTable was released in old versions of Java whereas ConcurrentHashMap is a java 5+ thing. 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