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Java TreeMap floorEntry() Method with Example

TreeMap Class floorEntry() method: Here, we are going to learn about the floorEntry() method of TreeMap Class with its syntax and example.
Submitted by Preeti Jain, on February 29, 2020

TreeMap Class floorEntry() method

• floorEntry() method is available in java.util package.
• floorEntry() method is used to return the key-value pair linked with the greatest key element less than or equal to the given key element (key_ele) when it exists.
• floorEntry() 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.
• floorEntry() method may throw an exception at the time of returning floor entry from this map.
  • ClassCastException: This exception may throw when the given parameter is incompatible to compare with.
  • NullPointerException: This exception may throw when the given element is null exists.

Syntax:

    public Map.Entry floorEntry(Key key_ele);

Parameter(s):

• Key key_ele – represents the key element to compare.

Return value:

The return type of the method is Map.Entry, it returns key-value pairs associated with the largest key element exists less than or equal to the given key element (key_ele) when exists otherwise it returns null.

Example:

// Java program to demonstrate the example 
// of Map.Entry floorEntry(Key key_ele) 
// method of TreeMap 

import java.util.*;

public class FloorEntryOfTreeMap {
    public static void main(String[] args) {
        // Instantiates TreeMap
        TreeMap < Integer, String > tm = new TreeMap < Integer, String > ();

        // By using put() method is
        // to put the key-value pairs in
        // treemap tm
        tm.put(1, "C");
        tm.put(4, "C++");
        tm.put(3, "Java");
        tm.put(2, "Php");

        // Display TreeMap tm
        System.out.println("tm: " + tm);

        // By using floorEntry(4) method is used
        // to return the largest key-value pair
        // less than or equal to the given key element
        // i.e. 4 ,"Java"

        // Display Returned Key-Value Element
        System.out.println("tm.floorEntry(4): " + tm.floorEntry(4));
    }
}

Output

tm: {1=C, 2=Php, 3=Java, 4=C++}
tm.floorEntry(4): 4=C++