Simple Java TreeSet example

This simple Java Example shows how to use Java TreeSet. It also describes how to add something to TreeSet object using add method.

import java.util.TreeSet;

public class SimpleJavaTreeSetExample {

 public static void main(String[] args) {

  // create object of TreeSet
  TreeSet tSet = new TreeSet();

  /**
   * Add an Object to TreeSet using boolean add(Object obj) method of Java
   * TreeSet class. This method adds an element to TreeSet if it is not
   * already present in TreeSet. It returns true if the element was added
   * to TreeSet, false otherwise.
   **/

  System.out.println("Adding 2:" + tSet.add(2));
  System.out.println("Adding 1:" + tSet.add(1));
  System.out.println("Adding 3:" + tSet.add(3));

  /** A set can't occupy duplicate elements, so returns false. **/

  System.out.println("Again adding 1:" + tSet.add(1));

  /**
   * TreeSet class guarantees that the sorted set will be in ascending
   * element order, sorted according to the natural order of the
   * elements;so here prints 1 2 3.
   **/
  System.out.println("TreeSet contains.." + tSet);
 }
}

The output is:



Adding 2:true
Adding 1:true
Adding 3:true
Again adding 1:false
TreeSet contains..[1, 2, 3]