Treeset overview
TreeSet is a java class which implements Set interface
Main features of TreeSet
It contains only unique elements, does not allow duplicates.
It stores elements in the sorted order
It does not maintain the insertion order, elements will be in sorted order.
It does not allow null value
We can create TreeSet using constructor as below
- TreeSet<String> ts = new TreeSet<String>();
TreeSet<String> ts = new TreeSet<String>();
Example
- import java.util.*;
- public class TreeSetExample {
- public static void main(String args[]) {
- TreeSet<String> ts = new TreeSet<String>();
- ts.add("java");
- ts.add("c");
- ts.add("c++");
- //Displaying TreeSet elements
- System.out.println(ts);
- }
- }
import java.util.*;
public class TreeSetExample {
public static void main(String args[]) {
TreeSet<String> ts = new TreeSet<String>();
ts.add("java");
ts.add("c");
ts.add("c++");
//Displaying TreeSet elements
System.out.println(ts);
}
}Note : We can observe in the output that elements are in sorted order
When to use TreeSet ?
TreeSet should be used whenever we want to store only unique elements in a collection and we want to store them in the sorted order
When not use TreeSet ?
TreeSet should not be used whenever we need to allow duplicate elements and we need to maintain the insertion order within the collection
