TreeSet Class
- TreeSet maintains the elements in ascending order. It doesn’t contain any duplicate value but it allows inserting null in the list.
- TreeSet class extents the AbstractSet class and implements NavigableSet interface.
Example : Program to implement different methods in TreeSet
import java.util.*;
public class TreeSetDemo
{
public static void main(String args[])
{
TreeSet<String> ts = new TreeSet<String>();
System.out.println("Intial size of TreeSet: "+ts.size());
//adding the elements
ts.add("ZZ");
ts.add("AA");
ts.add("BB");
ts.add("CC");
ts.add("DD");
ts.add("CC");
//ts.add(null); gives NullPointerException
System.out.println("TreeSet elements after adding: "+ts);
System.out.println("TreeSet is empty: "+ts.isEmpty());
System.out.println("Size of TreeSet : "+ts.size());
//delete the elements
ts.remove("BB");
System.out.println("TreeSet elemnts after deletion: "+ts);
}
}
Output:
Intial size of TreeSet: 0
TreeSet elements after adding: [AA, BB, CC, DD, ZZ]
TreeSet is empty: false
Size of TreeSet : 5
TreeSet elemnts after deletion: [AA, CC, DD, ZZ]
