AbstractMap remove() Method in Java with Examples
Last Updated :
26 Oct, 2018
The AbstractMap.remove() is an inbuilt method of AbstractMap class and is used to remove the mapping of any particular key from the map. It basically removes the values for any particular key in the Map.
Syntax:
AbstractMap.remove(Object key)
Parameters: The method takes one parameter key whose mapping is to be removed from the Map.
Return Value: The method returns the value that was previously mapped to the specified key if the key exists else the method returns NULL.
Below programs illustrates the working of AbstractMap.remove() method:
Program 1: When passing an existing key.
import java.util.*;
public class Abstract_Map_Demo {
public static void main(String[] args)
{
AbstractMap<Integer, String>
abs_map = new HashMap<Integer, String>();
abs_map.put( 10 , "Geeks" );
abs_map.put( 15 , "4" );
abs_map.put( 20 , "Geeks" );
abs_map.put( 25 , "Welcomes" );
abs_map.put( 30 , "You" );
System.out.println( "Initial Mappings are: "
+ abs_map);
String
returned_value
= (String)abs_map.remove( 20 );
System.out.println( "Returned value is: "
+ returned_value);
System.out.println( "New map is: "
+ abs_map);
}
}
|
Output:
Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Returned value is: Geeks
New map is: {25=Welcomes, 10=Geeks, 30=You, 15=4}
Program 2: When passing a new key.
import java.util.*;
public class Abstract_Map_Demo {
public static void main(String[] args)
{
AbstractMap<Integer, String>
abs_map = new HashMap<Integer, String>();
abs_map.put( 10 , "Geeks" );
abs_map.put( 15 , "4" );
abs_map.put( 20 , "Geeks" );
abs_map.put( 25 , "Welcomes" );
abs_map.put( 30 , "You" );
System.out.println( "Initial Mappings are: "
+ abs_map);
String
returned_value
= (String)abs_map.remove( 50 );
System.out.println( "Returned value is: "
+ returned_value);
System.out.println( "New map is: " + abs_map);
}
}
|
Output:
Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Returned value is: null
New map is: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.
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