What are the differences between a HashMap and a Hashtable in Java?

There are several differences between HashMap and Hashtable in Java:

  1. Hashtable is synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones.
  2. Hashtable does not allow null keys or values. HashMap allows one null key and any number of null values.
  3. One of HashMap’s subclasses is LinkedHashMap, so in the event that you’d want predictable iteration order (which is insertion order by default), you could easily swap out the HashMap for a LinkedHashMap. This wouldn’t be as easy if you were using Hashtable.

Since synchronization is not an issue for you, I’d recommend HashMap. If synchronization becomes an issue, you may also look at ConcurrentHashMap.

Related Posts:

  1. Difference between HashSet and HashMap?
  2. Java Ordered Map
  3. Hashtable, HashMap, HashSet , hash table concept in Java collection framework
  4. Easiest way to convert a List to a Set in Java
  5. ConcurrentHashMap and Hashtable in Java
  6. Any implementation of Ordered Set in Java?
  7. Any implementation of Ordered Set in Java?
  8. How to use Collections.sort() in Java?
  9. When to use LinkedList over ArrayList in Java?
  10. Difference between Arrays.asList(array) and new ArrayList(Arrays.asList(array))
  11. Is a Python dictionary an example of a hash table?
  12. Initialization of an ArrayList in one line
  13. How to sort an ArrayList?
  14. Exception in thread “main” java.lang.StackOverflowError
  15. Exception in thread “main” java.lang.StackOverflowError
  16. Iterate through a HashMap [duplicate]
  17. C# Java HashMap equivalent
  18. C# Java HashMap equivalent
  19. Iterate through a HashMap [duplicate]
  20. Why is there no SortedList in Java?
  21. What is the significance of load factor in HashMap?
  22. How to update a value, given a key in a hashmap?
  23. Collision resolution in Java HashMap
  24. How to convert List to int[] in Java?
  25. Difference between HashMap and Map in Java..?
  26. Printing HashMap In Java
  27. Java Hashmap: How to get key from value?
  28. How to convert int[] into List in Java?
  29. Sorting HashMap by values
  30. How do I efficiently iterate over each entry in a Java Map?
  31. How to sort Map values by key in Java?
  32. HashSet vs. ArrayList
  33. FIFO based Queue implementations?
  34. HashMap get/put complexity
  35. What is a hash map in programming and where can it be used
  36. Create a List of primitive int?
  37. What is the difference between the HashMap and Map objects in Java?
  38. How to convert int[] to Integer[] in Java?
  39. Change priorityQueue to max priorityqueue
  40. Collections.emptyMap() vs new HashMap()
  41. “Cannot create generic array of ..” – how to create an Array of Map?
  42. Sort a Map by values
  43. Good Hash Function for Strings
  44. Most efficient way to increment a Map value in Java
  45. What is a hash function in java?
  46. Printing a java map Map – How?
  47. Why is a ConcurrentModificationException thrown and how to debug it
  48. How to sort a HashSet?
  49. Union or intersection of Java Sets
  50. What is a hash function in java?
  51. Map of maps – how to keep the inner maps as maps?
  52. toring and Retrieving ArrayList values from hashmap
  53. Java associative-array
  54. What does Java option -Xmx stand for? [duplicate]
  55. How do I convert a String to an int in Java?
  56. What does Java option -Xmx stand for? [duplicate]
  57. Is there an invisible character that is not regarded as whitespace?
  58. Problem with gif with transparent background
  59. Finding white rectangle in an image
  60. 1000 * 60 * 60 * 24 * 30 results in a negative number [duplicate]
  61. How to convert nanoseconds to seconds using the TimeUnit enum?
  62. Search for words with telephone numbers from 2-3-4 tree
  63. How to do associative array/hashing in JavaScript
  64. Using or ‘|’ in regex [duplicate]
  65. How to format strings in Java
  66. What is the difference between x86 and x64
  67. && (AND) and || (OR) in IF statements
  68. How to use the toString method in Java?
  69. What is a NullPointerException, and how do I fix it?
  70. What exactly is Apache Camel?
  71. Unable to find valid certification path to requested target – error even after cert imported
  72. Unable to find valid certification path to requested target – error even after cert imported
  73. What is the equivalent of the C++ Pair in Java?
  74. Java – Convert integer to string [duplicate]
  75. Getting random numbers in Java [duplicate]
  76. What is an instance variable in Java?
  77. javac is not recognized as an internal or external command, operable program or batch file [closed]
  78. javac is not recognized as an internal or external command, operable program or batch file [closed]
  79. Java: “error: cannot find symbol”
  80. How does the Java ‘for each’ loop work?
  81. Which is the difference between Long.valueOf(0) and 0L in Java?
  82. What is a StackOverflowError?
  83. Use of “instanceof” in Java [duplicate]
  84. What is the best way to use a HashMap in C++?
  85. What is the best way to use a HashMap in C++?
  86. How to uninstall Eclipse?
  87. Is GNU’s Java Compiler (GCJ) dead? [closed]
  88. How does System.out.print() work?
  89. How do I “decompile” Java class files? [closed]
  90. How do I determine whether an array contains a particular value in Java?
  91. How to initialize an array in Java?
  92. How does the Java ‘for each’ loop work?
  93. Java 8 Iterable.forEach() vs foreach loop
  94. Initialize part of an array in java
  95. How can I solve Exception in thread “main” java.lang.NullPointerException error [duplicate]
  96. How to split a string in Java
  97. What does “Could not find or load main class” mean?
  98. What does “Could not find or load main class” mean?
  99. Why am I getting a NoClassDefFoundError in Java?
  100. How to avoid “ConcurrentModificationException” while removing elements from `ArrayList` while iterating it? [duplicate]

Leave a Comment

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)