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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. import java.util.concurrent.* ;
  8.  
  9. /* Name of the class has to be "Main" only if the class is public. */
  10. class Ideone
  11. {
  12. 	public static void main (String[] args) throws java.lang.Exception
  13. 	{
  14.  
  15. ConcurrentMap< String , Set< String> > personFavoriteColors = new ConcurrentSkipListMap<>() ;
  16.  
  17. personFavoriteColors.computeIfAbsent( 
  18.     "Alice" , 
  19.     ( x -> new CopyOnWriteArraySet<>())).add( "Purple" )
  20. ;
  21.  
  22. personFavoriteColors.computeIfAbsent( 
  23.     "Alice" , 
  24.     ( x -> new CopyOnWriteArraySet<>())).add( "Gold" )
  25. ;
  26.  
  27. List< String > favoriteColorsForAlice = personFavoriteColors.get( "Alice" ) ;
  28.  
  29. System.out.println( favoriteColorsForAlice ) ; 
  30.  
  31.  
  32. 	}
  33. }
Success #stdin #stdout 0.11s 33824KB
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[Purple, Gold]
https://ideone.com/xw0ZGH
language:
Java (HotSpot 12)
created:
6 years ago
visibility:
public

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