HashMap and ConcurrentHashMap - Similarity and Differences
HashMap vs Hashtable vs LinkedHashMap vs TreeMap - Differences
Map hierarchy in java - Detailed - HashMap, Hashtable, ConcurrentHashMap, LinkedHashMap, TreeMap, ConcurrentSkipListMap, IdentityHashMap
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/** Copyright (c), AnkitMittal JavaMadeSoEasy.com */
public class ConcurrentHashMapUnmodifiableExample {
public static void main(String args[]){
Map<Integer,String> concurrentHashMap=new ConcurrentHashMap<Integer,String>();
concurrentHashMap.put(11, "ankit");
concurrentHashMap.put(21, "mittal");
concurrentHashMap.put(31, "javaMadeSoEasy");
//getting unmodifiable ConcurrentHashMap
Map<Integer,String> unmodifiableMap = Collections.unmodifiableMap(concurrentHashMap);
/*
* Now any attempt to modify map will throw java.lang.UnsupportedOperationException
*/
unmodifiableMap.put(41,"java");
}
}
/*OUTPUT
Exception in thread "main" java.lang.UnsupportedOperationException
at java.util.Collections$UnmodifiableMap.put(Unknown Source)
at ConcurrentHashMap_unmodifiable.ConcurrentHashMapUnmodifiableExample.main(ConcurrentHashMapUnmodifiableExample.java:24)
*/
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RELATED LINKS>
HashMap - Iterate on keys by obtaining keySet, Iterate on values by obtaining values, Iterate on entry by obtaining entrySet
HashMap - synchronizing map using Collections.synchronizedMap
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Core Java