{"id":11089,"date":"2024-03-14T13:23:33","date_gmt":"2024-03-14T13:23:33","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/what-is-the-difference-between-hashmap-and-hashtable\/"},"modified":"2025-08-04T07:28:22","modified_gmt":"2025-08-04T07:28:22","slug":"what-is-the-difference-between-hashmap-and-hashtable","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/what-is-the-difference-between-hashmap-and-hashtable\/","title":{"rendered":"HashMap vs Hashtable: Key Differences"},"content":{"rendered":"

HashMap and Hashtable are both collection classes used to store key-value pairs, but they have a few differences between them:<\/p>\n

    \n
  1. Thread safety: Hashtable is thread-safe, meaning it is safe to operate on Hashtable in a multi-threaded environment. In contrast, HashMap is not thread-safe, so additional synchronization measures are required to ensure thread safety when operating on HashMap in a multi-threaded environment.<\/li>\n
  2. The value of null: Hashtable does not allow storing null keys or values. If an attempt is made to insert a null key or value into Hashtable, a NullPointerException will be thrown. On the other hand, HashMap allows storing one null key and multiple null values.<\/li>\n
  3. Inheritance relationships: Hashtable is a thread-safe class, while HashMap is not. Hashtable is a subclass of Dictionary, while HashMap is a subclass of AbstractMap.<\/li>\n
  4. Performance: HashMap is generally faster than Hashtable because HashMap is not thread-safe and does not incur the overhead of thread synchronization. In a single-threaded environment, HashMap is usually faster than Hashtable.<\/li>\n<\/ol>\n

    In conclusion, generally speaking, if thread safety is not needed and the existence of null values is acceptable, it is recommended to use HashMap; if thread safety is required, Hashtable can be considered.<\/p>\n","protected":false},"excerpt":{"rendered":"

    HashMap and Hashtable are both collection classes used to store key-value pairs, but they have a few differences between them: Thread safety: Hashtable is thread-safe, meaning it is safe to operate on Hashtable in a multi-threaded environment. In contrast, HashMap is not thread-safe, so additional synchronization measures are required to ensure thread safety when operating […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[224,576,14139,87,396],"class_list":["post-11089","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-data-structures","tag-hashmap","tag-hashtable","tag-java","tag-thread-safety"],"yoast_head":"\nHashMap vs Hashtable: Key Differences - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Learn core differences between HashMap and Hashtable: thread safety, null handling, and performance in Java data structures.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/what-is-the-difference-between-hashmap-and-hashtable\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"HashMap vs Hashtable: Key Differences\" \/>\n<meta property=\"og:description\" content=\"Learn core differences between HashMap and Hashtable: thread safety, null handling, and performance in Java data structures.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/what-is-the-difference-between-hashmap-and-hashtable\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - 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