Map putAll() Method in Java with Examples
This method is used to copy all of the mappings from the specified map to this map.
Syntax:
void putAll(Map m)
Parameters: This method has the only argument map m, which contains key-value mappings to be copied to given map.
Returns: This method returns previous value associated with the key if present, else return -1.
Below programs show the implementation of int putAll() method.
Program 1:
// Java code to show the implementation of // putAll method in Map interface import java.util.*; public class GfG { // Driver code public static void main(String[] args) { // Initializing a Map of type HashMap Map<Integer, String> map = new HashMap<>(); map.put( 1 , "One" ); map.put( 3 , "Three" ); map.put( 5 , "Five" ); map.put( 7 , "Seven" ); map.put( 9 , "Nine" ); System.out.println(map); Map<Integer, String> mp = new HashMap<>(); mp.put( 10 , "Ten" ); mp.put( 30 , "Thirty" ); mp.put( 50 , "Fifty" ); map.putAll(mp); System.out.println(map); } } |
Output:
{1=One, 3=Three, 5=Five, 7=Seven, 9=Nine} {1=One, 50=Fifty, 3=Three, 5=Five, 7=Seven, 9=Nine, 10=Ten, 30=Thirty}
Program 2: Below is the code to show implementation of put().
// Java code to show the implementation of // putAll method in Map interface import java.util.*; public class GfG { // Driver code public static void main(String[] args) { // Initializing a Map of type HashMap Map<String, String> map = new HashMap<>(); map.put( "1" , "One" ); map.put( "3" , "Three" ); map.put( "5" , "Five" ); map.put( "7" , "Seven" ); map.put( "9" , "Nine" ); System.out.println(map); Map<String, String> mp = new HashMap<>(); mp.put( "10" , "Ten" ); mp.put( "30" , "Thirty" ); mp.put( "50" , "Fifty" ); map.putAll(mp); System.out.println(map); } } |
Output:
{1=One, 3=Three, 5=Five, 7=Seven, 9=Nine} {1=One, 3=Three, 5=Five, 7=Seven, 9=Nine, 50=Fifty, 30=Thirty, 10=Ten}
Reference:
Oracle Docs
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