What is Hashtable method?

What is Hashtable method?

In computing, a hash table (hash map) is a data structure that implements an associative array abstract data type, a structure that can map keys to values. A hash table uses a hash function to compute an index, also called a hash code, into an array of buckets or slots, from which the desired value can be found.

What is Hashtable and how it works?

Hashtable is a kind of Hash map but is synchronized. The Hash table of Java holds a class that has unique elements. Working of Hashtable. Hash table intrinsically contains a slot/bucket in which the storage of key and value pair. It uses the key’s hash code to discover which bucket the key/value of a set should map.

Is Threadsafe a Hashtable?

Yes Hashtable is thread safe, If a thread safe is not needed in your application then go through HashMap, In case, If a thread-safe implementation is desired,then it is recommended to use ConcurrentHashMap in place of Hashtable.

How do you create a hash table?

Creating Hash Tables

1. Begin the hash table with an at sign ( @ ).
2. Enclose the hash table in braces ( {} ).
3. Enter one or more key/value pairs for the content of the hash table.
4. Use an equal sign ( = ) to separate each key from its value.
5. Use a semicolon ( ; ) or a line break to separate the key/value pairs.

Is Hashtable a member of collection framework?

Hashtable was part of the original java. Thus, Hashtable is now integrated into the collections framework. It is similar to HashMap, but is synchronized. Like HashMap, Hashtable stores key/value pairs in a hash table.

What is difference between HashMap and Hashtable?

HashMap is non-synchronized. It is not thread-safe and can’t be shared between many threads without proper synchronization code whereas Hashtable is synchronized. HashMap allows one null key and multiple null values whereas Hashtable doesn’t allow any null key or value.

What is difference between ConcurrentHashMap and Hashtable?

Hashtable uses single lock for whole data. ConcurrentHashMap uses multiple locks on segment level (16 by default) instead of object level i.e. whole Map . ConcurrentHashMap locking is applied only for updates. So reads can happen very fast while writes are done with a lock.