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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.HashMap;
  4. import java.util.Map;
  5. import java.util.Map.Entry;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static <T, E> T getKeyByValue(Map<T, E> map, E value) {
  11.  
  12. 	    for (Entry<T, E> entry : map.entrySet()) {
  13.  
  14. 	        if (value.equals(entry.getValue())) {
  15. 	            return entry.getKey();
  16. 	        }
  17. 	    }
  18.  
  19. 	    return null;
  20. 	}
  21.  
  22. 	public static void main (String[] args) throws java.lang.Exception
  23. 	{
  24. 		Map<String,String> myMap = new HashMap<String,String>();
  25. 		myMap.put("1","valor1");
  26. 		myMap.put("2","valor2");
  27. 		myMap.put("3","valor3");
  28.  
  29. 		System.out.println(getKeyByValue(myMap,"valor1"));
  30. 	}
  31. }
Success #stdin #stdout 0.1s 320576KB
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https://ideone.com/Wrw2gf
language:
Java (HotSpot 12)
created:
8 years ago
visibility:
public

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