Which One is optimal to choose ? Syncronized hash map or Hash table with sing

Which One is optimal to choose ?

Syncronized hash map or Hash table with single thread model?

How can a hash map syncronized with out using syncrozed
blocks in programm?

Question Posted / vijay bhaskar

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Which One is optimal to choose ? Syncronized hash map or Hash table with single thread model? ..

Answer / ranganathkini

The java.util.Hashtable provides a synchronized collection
implementation to store key-value pairs. Hence
synchronization of a Hashtable is not necessary.

Synchronization has a performance overhead and therfore must
be used with caution in only those situations where a
resource(s) is shared by multiple threads. Hence a
java.util.HashMap implementation can be used for single
threaded model and it can be externally synchronized if it
is to be used in a mult-threaded model.

To get a synchronized version of a java.util.HashMap without
using synchronized blocks, do this:

// make sure this is in imports
import java.util.*;

// our unsynchronized map object
Map myMap = new HashMap();

// get a synchronized map from our unsynchronized map
Map mySyncMap = Collections.synchronizedMap( myMap );

After this, all access to the map must be via mySyncMap
reference and NOT myMap.

Another way to acquire a synchronized map is:

Map mySyncMap = Collections.synchronizedMap( new HashMap() );

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Which One is optimal to choose ? Syncronized hash map or Hash table with single thread model? ..

Answer / ravikiran

Collections.synchronizedMap()

Is This Answer Correct ?

2 Yes

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Which One is optimal to choose ? Syncronized hash map or Hash table with single thread model? ..

Answer / dsr

Collections.synchronizedMap(HashMap object)

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1 Yes

1 No

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