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Simple Java TreeSet example

  1. /*
  2.   Simple Java TreeSet example
  3.   This simple Java Example shows how to use Java TreeSet. It also describes how to
  4.   add something to TreeSet object using add method.
  5. */
  6.  
  7. import java.util.TreeSet;;
  8.  
  9. public class SimpleJavaTreeSetExample {
  10.  
  11.   public static void main(String[] args) {
  12.    
  13.     //create object of TreeSet
  14.     TreeSet tSet = new TreeSet();
  15.    
  16.     /*
  17.       Add an Object to TreeSet using
  18.       boolean add(Object obj) method of Java TreeSet class.
  19.       This method adds an element to TreeSet if it is not already present in TreeSet.
  20.       It returns true if the element was added to TreeSet, false otherwise.
  21.     */
  22.    
  23.     tSet.add(new Integer("1"));
  24.     tSet.add(new Integer("2"));
  25.     tSet.add(new Integer("3"));
  26.    
  27.     /*
  28.       Please note that add method accepts Objects. Java Primitive values CAN NOT
  29.       be added directly to TreeSet. It must be converted to corrosponding
  30.       wrapper class first.
  31.     */
  32.    
  33.     System.out.println("TreeSet contains.." + tSet);  
  34.   }
  35. }
  36.  
  37. /*
  38. Output of the program would be
  39. TreeSet contains..[1, 2, 3]
  40. */