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MessagePack is more compact than JSON, but imposes limitations on array and integer sizes.On the other hand, it allows binary data and non-UTF-8 encoded strings. In JSON, map keys have to be strings, but in MessagePack there is no such limitation and any type can be a map key, including types like maps and arrays, and, like YAML, numbers.
For unordered access as defined in the java.util.Map interface, the java.util.concurrent.ConcurrentHashMap implements java.util.concurrent.ConcurrentMap. [2] The mechanism is a hash access to a hash table with lists of entries, each entry holding a key, a value, the hash, and a next reference.
A map implemented by a hash table is called a hash map. Most hash table designs employ an imperfect hash function . Hash collisions , where the hash function generates the same index for more than one key, therefore typically must be accommodated in some way.
Rather than having a single instance per application (e.g. the java.lang.Runtime object in the Java programming language) the multiton pattern instead ensures a single instance per key. The multiton pattern does not explicitly appear as a pattern in the highly regarded object-oriented programming textbook Design Patterns. [1]
In computer science, a multimap (sometimes also multihash, multidict or multidictionary) is a generalization of a map or associative array abstract data type in which more than one value may be associated with and returned for a given key. Both map and multimap are particular cases of containers (for example, see C++ Standard Template Library ...
Download and install the latest Java Virtual Machine in Internet Explorer. 1. Go to www.java.com. 2. Click Free Java Download. 3. Click Agree and Start Free Download. 4. Click Run. Notes: If prompted by the User Account Control window, click Yes. If prompted by the Security Warning window, click Run. 5.
Maps are data structures that associate a key with an element. This lets the map be very flexible. If the key is the hash code of the element, the Map is essentially a Set. If it's just an increasing number, it becomes a list. Examples of Map implementations include java.util.HashMap, java.util.LinkedHashMap, and java.util.TreeMap.
OpenStreetMap (abbreviated OSM) is a free, open map database updated and maintained by a community of volunteers via open collaboration. [4] Contributors collect data from surveys, trace from aerial photo imagery or satellite imagery, and import from other freely licensed geodata sources.