TreeSet isEmpty() Method in Java (original) (raw)

Last Updated : 26 Nov, 2018

The Java.util.TreeSet.isEmpty() method is used to check and verify if a TreeSet is empty or not. It returns True if the TreeSet is empty else it returns False.Syntax:

Tree_Set.isEmpty()

Parameters: The method does not take any parameterReturn Value: The function returns True if the set is empty else it returns False. Below program illustrate the use of Java.util.TreeSet.isEmpty() method:

Java `

// Java code to illustrate isEmpty() method import java.util.*; import java.util.TreeSet;

public class TreeSetDemo { public static void main(String args[]) { // Creating an empty HashSet TreeSet tree = new TreeSet();

    // Use add() method to add elements into the Set
    tree.add("Welcome");
    tree.add("To");
    tree.add("Geeks");
    tree.add("4");
    tree.add("Geeks");
    tree.add("TreeSet");

    // Displaying the TreeSet
    System.out.println("TreeSet: " + tree);

    // Check for the empty set
    System.out.println("Is the set empty? " + tree.isEmpty());

    // Clearing the set using clear() method
    tree.clear();

    // Again Checking for the empty set
    System.out.println("Is the set empty? " + tree.isEmpty());
}

}

`

Output:

TreeSet: [4, Geeks, To, TreeSet, Welcome] Is the set empty? false Is the set empty? true

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