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Guilherme Mazui

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What is the Difference Between Hashtable and Hashmap?

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The main differences between Hashtable and HashMap in Java are:

  1. Thread Safety: Hashtable is synchronized, which means it can be shared between multiple threads and is thread-safe. HashMap, on the other hand, is non-synchronized, meaning it cannot be accessed by multiple threads without additional synchronization code.
  2. Null Values: HashMap allows one null key and multiple null values, while Hashtable does not allow any null keys or values.
  3. Performance: HashMap generally offers better performance than Hashtable since it is non-synchronized, making it faster in single-thread applications.

In summary, if thread synchronization is not needed, HashMap is generally preferred over Hashtable due to its better performance and ability to handle null values. However, if you require thread safety, you should use Hashtable or a synchronized version of HashMap.

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  • What is the Difference Between Hashtable and Hashmap?
  • Comparative Table: Hashtable vs Hashmap

    • Comparative Table: Hashtable vs Hashmap

    Here is a table comparing the differences between Hashtable and HashMap in Java:

    Feature HashMap Hashtable
    Synchronization Not synchronized, not thread-safe Synchronized, thread-safe
    Null values Allows one null key and multiple null values Doesn't allow any null key or value
    Performance Faster due to no synchronization Slower because of synchronization
    Use case Preferred for non-threaded applications Recommended for multithreaded implementations
    Synchronization method Cannot be directly synchronized Can be unsynchronized using Collections.synchronizedMap()
    Order Does not guarantee constant order over time Order remains constant over time

    HashMap and Hashtable are both data structures that map keys to values. HashMap is not synchronized, making it faster and suitable for non-threaded applications. On the other hand, Hashtable is synchronized, making it thread-safe and suitable for multithreaded implementations.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.