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Check if a particular key exists in Java TreeMap example

  1. /*
  2.   Check if a particular key exists in Java TreeMap example
  3.   This Java Example shows how to check if TreeMap object contains a particular
  4.   key using containsKey method of TreeMap class.
  5. */
  6.  
  7. import java.util.TreeMap;
  8.  
  9. public class CheckKeyOfTreeMapExample {
  10.  
  11.   public static void main(String[] args) {
  12.    
  13.     //create TreeMap object
  14.     TreeMap treeMap = new TreeMap();
  15.    
  16.     //add key value pairs to TreeMap
  17.     treeMap.put("1","One");
  18.     treeMap.put("2","Two");
  19.     treeMap.put("3","Three");
  20.    
  21.     /*
  22.       To check whether a particular key exists in TreeMap use
  23.       boolean containsKey(Object key) method of TreeMap class.
  24.       It returns true if the TreeMap contains mapping for specified key
  25.       otherwise false.
  26.     */
  27.    
  28.     boolean blnExists = treeMap.containsKey("1");
  29.     System.out.println("1 exists in TreeMap ? : " + blnExists);
  30.   }
  31. }
  32.  
  33. /*
  34. Output would be
  35. 1 exists in TreeMap ? : true
  36. */