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Java TreeSet lower() Method with Example

TreeSet Class lower() method: Here, we are going to learn about the lower() method of TreeSet Class with its syntax and example.
Submitted by Preeti Jain, on February 20, 2020

TreeSet Class lower() method

• lower() method is available in java.util package.
• lower() method is used to return the largest element in this TreeSet that is lower than the specified element (ele) when it exists otherwise it returns null.
• lower() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• lower() method may throw an exception at the time of returning the element.
  • ClassCastException: This exception may throw when the given parameter is incompatible to compare.
  • NullPointerException: This exception may throw when the given element is null exists.

Syntax:

    public Element lower(Element ele);

Parameter(s):

• Element ele – represents the element (ele) is to be checked with other element exists in this TreeSet.

Return value:

The return type of the method is Element, it returns highest element lower than the given element (ele) in this TreeSet otherwise it returns null when no such element exists.

Example:

// Java program to demonstrate the example 
// of Element lower(Element ele) method of TreeSet 

import java.util.*;

public class LowerOfTreeSet {
    public static void main(String[] args) {
        // Instantiates a TreeSet object
        TreeSet < String > tree_set = new TreeSet < String > ();

        // By using add() method is to add
        // the given object of this TreeSet 
        tree_set.add("C");
        tree_set.add("C++");
        tree_set.add("JAVA");
        tree_set.add("PHP");
        tree_set.add("SFDC");

        // Display TreeSet
        System.out.println("TreeSet: " + tree_set);

        // By using lower() method is to
        // return the greatest element
        // less than the given element
        // exists in this TreeSet
        Object greatest = tree_set.lower("DataScience");

        // Display Greatest
        System.out.println("tree_set.lower(): " + greatest);
    }
}

Output

TreeSet: [C, C++, JAVA, PHP, SFDC]
tree_set.lower(): C++