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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static void main (String[] args) throws java.lang.Exception
  11. 	{
  12. 		List< Map< String, String > > listOfMapsOfNames = new ArrayList<>() ;
  13. 		Map< String, String > mapOfNames = new HashMap<>() ;
  14.  
  15. 		mapOfNames.put( "name", "John" );
  16. 		mapOfNames.put( "lastname", "McKoy" );
  17. 		listOfMapsOfNames.add( Map.copyOf( mapOfNames ) );  // Make an unmodifiable copy of map to be added to list.
  18.  
  19. 		System.out.println( "map before clear: " + mapOfNames );
  20. 		mapOfNames.clear();
  21. 		System.out.println( "map after clear: " + mapOfNames );
  22.  
  23. 		mapOfNames.put( "name", "Tom" );
  24. 		mapOfNames.put( "lastname" , "Red" );
  25. 		listOfMapsOfNames.add( Map.copyOf( mapOfNames ) );  // Make an unmodifiable copy of map to be added to list.
  26.  
  27. 		System.out.println( "map after 2nd add: " + mapOfNames );
  28. 		System.out.println( "list at the end: " + listOfMapsOfNames );
  29. 	}
  30. }
Success #stdin #stdout 0.09s 53900KB
comments (?)
stdin 
Standard input is empty
stdout 
map before clear: {name=John, lastname=McKoy}
map after clear: {}
map after 2nd add: {name=Tom, lastname=Red}
list at the end: [{name=John, lastname=McKoy}, {name=Tom, lastname=Red}]
https://ideone.com/mhUsR2
language:
Java (HotSpot 12)
created:
4 years ago
visibility:
public

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