Maps in Java - Revision history

Admin: Fix critical errors: Map is an interface not abstract class; add missing implementations (ConcurrentHashMap, WeakHashMap, IdentityHashMap, EnumMap); fix Hashtable description; add interface hierarchy (SortedMap, NavigableMap, ConcurrentMap); consistent Java 8 doc links; remove informal placeholder text; add comparison table; improve HashMap description with tree-bin details (via update-page on MediaWiki MCP Server)

2026-06-08T04:25:29Z

Fix critical errors: Map is an interface not abstract class; add missing implementations (ConcurrentHashMap, WeakHashMap, IdentityHashMap, EnumMap); fix Hashtable description; add interface hierarchy (SortedMap, NavigableMap, ConcurrentMap); consistent Java 8 doc links; remove informal placeholder text; add comparison table; improve HashMap description with tree-bin details (via update-page on MediaWiki MCP Server)

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Admin: /* LinkedHashMap */

2017-06-29T06:59:19Z

LinkedHashMap

← Older revision		Revision as of 06:59, 29 June 2017
Line 143:		Line 143:
	</pre>		</pre>

	Here on line 199 we see the double pointers of head and tail for this doubly-linked list:		Here on line 199 we see the double pointers of head and tail for this doubly-linked list: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/LinkedHashMap.java#l199

	<pre>		<pre>
Line 157:		Line 157:
	</pre>		</pre>

	The way this class is organized is to implement private utility methods, and expose a public API that utilizes those private utility classes. For example, the add method uses the linkNodeLast() method:		The way this class is organized is to implement private utility methods, and expose a public API that utilizes those private utility classes. For example, the add method uses the linkNodeLast() method: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/LinkedHashMap.java#l217

	<pre>		<pre>

Admin: /* LinkedHashMap */

2017-06-21T06:39:40Z

LinkedHashMap

@@ Line 155: / Line 155: @@
       */
      transient LinkedHashMap.Entry<K,V> tail;
 </pre>

Admin: /* LinkedHashMap */

2017-06-21T06:38:09Z

LinkedHashMap

@@ Line 128: / Line 128: @@
 ==LinkedHashMap==
-There is also a LinkedHashMap, which implements a Hash Map using a linked structure: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/LinkedHashMap.java
+There is also a LinkedHashMap, which implements a Hash Map using a linked structure. This is a child class of HashMap. "This implementation differs from HashMap in that it maintains a doubly-linked list running through all of its entries."
 ==Hashtable==

Admin: /* Flags */

2017-06-21T06:34:01Z

Flags

← Older revision		Revision as of 06:34, 21 June 2017
Line 136:		Line 136:

	=Flags=		=Flags=

			{{MapsFlag}}

			[[Category:Java]]
			[[Category:Collections]]
			[[Category:Maps]]

Admin: /* TreeMap */

2017-06-21T06:33:37Z

TreeMap

← Older revision		Revision as of 06:33, 21 June 2017
Line 120:		Line 120:
	==TreeMap==		==TreeMap==

	TreeMap is a slower, O(log N) map that uses a tree structure to store data in a sorted fashion. This provides faster access to max/min of data. ~~TreeMap.java Link~~: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/TreeMap.java		TreeMap is a slower, O(log N) map that uses a tree structure to store data in a sorted fashion. This provides faster access to max/min of data.

			Source: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/TreeMap.java

			Documentation: http://docs.oracle.com/javase/8/docs/api/java/util/TreeMap.html

	==LinkedHashMap==		==LinkedHashMap==

Admin: /* HashMap */

2017-06-21T06:23:09Z

HashMap

@@ Line 95: / Line 95: @@
 Documentation: http://docs.oracle.com/javase/8/docs/api/java/util/HashMap.html
-* HashMap extends the abstract map type
+* HashMap class extends the abstract map type
 * This is similar to the Hashtable class (see below), except that it is unsynchronized and accepts null values and null keys
 * This provides constant time get and put functions, assuming hash function disperses among buckets properly
 * Two parameters, initial capacity and load factor, set performance of object
 ==TreeMap==

Admin: /* HashMap */

2017-06-21T06:21:03Z

HashMap

← Older revision		Revision as of 06:21, 21 June 2017
Line 89:		Line 89:
	==HashMap==		==HashMap==

	HashMap is a faster, O(1) map that uses a hash table to store data but stores the data in an unsorted fashion. ~~HashMap.java Link~~: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/HashMap.java		HashMap is a faster, O(1) map that uses a hash table to store data but stores the data in an unsorted fashion.

			Source: http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/ff6c76f7733e/src/share/classes/java/util/HashMap.java

			Documentation: http://docs.oracle.com/javase/8/docs/api/java/util/HashMap.html

			* HashMap extends the abstract map type
			* This is similar to the Hashtable class (see below), except that it is unsynchronized and accepts null values and null keys
			* This provides constant time get and put functions, assuming hash function disperses among buckets properly
			* Two parameters, initial capacity and load factor, set performance of object

	==TreeMap==		==TreeMap==

Admin: /* AbstractMap */

2017-06-21T05:22:22Z

AbstractMap

@@ Line 56: / Line 56: @@
+     }
 </pre>
 ==HashMap==

Admin: /* AbstractMap */

2017-06-21T05:19:58Z

AbstractMap

@@ Line 32: / Line 32: @@
       */
      protected AbstractMap() {
+     }
 </pre>