Java Creating a TreeSet

A TreeSet is a collection that is implemented as a tree data structure in Java. It extends the AbstractSet class and implements the NavigableSet interface. A TreeSet stores its elements in a sorted order, and it does not allow duplicate elements.

Here is an example of how to create a TreeSet in Java:

import java.util.TreeSet;

public class Main {
  public static void main(String[] args) {
    // Create a TreeSet
    TreeSet<String> set = new TreeSet<>();

    // Add elements to the TreeSet
    set.add("Apple");
    set.add("Banana");
    set.add("Cherry");
    set.add("Date");
    set.add("Elderberry");

    // Print the TreeSet
    System.out.println(set);  // Output: [Apple, Banana, Cherry, Date, Elderberry]
  }
}

In this example, we create a TreeSet of type String and add some elements to it. The TreeSet stores the elements in alphabetical order.

You can also create a TreeSet with a custom comparator, which specifies the order in which the elements should be stored. Here is an example:

import java.util.Comparator;
import java.util.TreeSet;

public class Main {
  public static void main(String[] args) {
    // Create a comparator that sorts strings in reverse alphabetical order
    Comparator<String> comparator = (s1, s2) -> s2.compareTo(s1);

    // Create a TreeSet with the custom comparator
    TreeSet<String> set = new TreeSet<>(comparator);

    // Add elements to the TreeSet
    set.add("Apple");
    set.add("Banana");
    set.add("Cherry");
    set.add("Date");
    set.add("Elderberry");

    // Print the TreeSet
    System.out.println(set);  // Output: [Elderberry, Date, Cherry, Banana, Apple]
  }
}

In this example, we create a comparator that sorts strings in reverse alphabetical order, and pass it to the TreeSet constructor when creating the TreeSet. The TreeSet will use this comparator to sort the elements in the specified order.