The synchronizedMap() method of java.util.Collections class is used to return a synchronized (thread-safe) map backed by the specified map. In order to guarantee serial access, it is critical that all access to the backing map is accomplished through the returned map.
Syntax:
public static <K, V> Map<K, V> synchronizedMap(Map<K, V> m)
Parameters: This method takes the map as a parameter to be “wrapped” in a synchronized map.
Return Value: This method returns a synchronized view of the specified map.
Below are the examples to illustrate the synchronizedMap() method.
Example 1:
// Java program to demonstrate // synchronizedMap() method // for <String, String> Value import java.util.*;
public class GFG1 {
public static void main(String[] argv)
throws Exception
{
try {
// creating object of Map<String, String>
Map<String, String>
map = new HashMap<String, String>();
// populate the map
map.put( "Value1" , "20" );
map.put( "Value2" , "30" );
map.put( "Value3" , "40" );
// printing the Collection
System.out.println( "Map : " + map);
// create a synchronized map
Map<String, String>
synmap = Collections.synchronizedMap(map);
// printing the Collection
System.out.println( "Synchronized map is : "
+ synmap);
}
catch (IllegalArgumentException e) {
System.out.println( "Exception thrown : " + e);
}
}
} |
Map : {Value3=40, Value1=20, Value2=30} Synchronized map is : {Value3=40, Value1=20, Value2=30}
Example 2:
// Java program to demonstrate // synchronizedMap() method // for <String, Boolean> Value import java.util.*;
public class GFG1 {
public static void main(String[] argv)
throws Exception
{
try {
// creating object of Map<String, Boolean>
Map<String, Boolean>
map = new HashMap<String, Boolean>();
// populate the map
map.put( "Bramha" , true );
map.put( "Vishnu" , true );
map.put( "Mahesh" , true );
// printing the Collection
System.out.println( "Map : " + map);
// create a synchronized map
Map<String, Boolean>
synmap = Collections.synchronizedMap(map);
// printing the Collection
System.out.println( "Synchronized map is : "
+ synmap);
}
catch (IllegalArgumentException e) {
System.out.println( "Exception thrown : " + e);
}
}
} |
Map : {Bramha=true, Vishnu=true, Mahesh=true} Synchronized map is : {Bramha=true, Vishnu=true, Mahesh=true}