TreeMap lastKey() Method in Java Last Updated : 09 Jul, 2018 Comments Improve Suggest changes Like Article Like Report The java.util.TreeMap.lastKey() is used to retrieve the last or the highest key present in the map. Syntax: tree_map.lastKey() Parameters: The method does not take any parameters. Return Value: The method returns the last key present in the map. Exception: The method throws NoSuchElementException if the map is empty. Below programs illustrate the working of java.util.TreeMap.lastKey() method: Program 1: Java // Java code to illustrate the lastKey() method import java.util.*; public class Tree_Map_Demo { public static void main(String[] args) { // Creating an empty TreeMap TreeMap<Integer, String> tree_map = new TreeMap<Integer, String>(); // Mapping string values to int keys tree_map.put(10, "Geeks"); tree_map.put(15, "4"); tree_map.put(20, "Geeks"); tree_map.put(25, "Welcomes"); tree_map.put(30, "You"); // Displaying the TreeMap System.out.println("The Mappings are: " + tree_map); // Displaying the lastKey of the map System.out.println("The last key is " + tree_map.lastKey()); } } Output: The Mappings are: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You} The last key is 30 Program 2: Java // Java code to illustrate the lastKey() method import java.util.*; public class Tree_Map_Demo { public static void main(String[] args) { // Creating an empty TreeMap TreeMap<String, Integer> tree_map = new TreeMap<String, Integer>(); // Mapping int values to string keys tree_map.put("Geeks", 10); tree_map.put("4", 15); tree_map.put("Geeks", 20); tree_map.put("Welcomes", 25); tree_map.put("You", 30); // Displaying the TreeMap System.out.println("The Mappings are: " + tree_map); // Displaying the lastKey of the map System.out.println("The last key is " + tree_map.lastKey()); } } Output: The Mappings are: {4=15, Geeks=20, Welcomes=25, You=30} The last key is You Comment More infoAdvertise with us Next Article TreeMap lastKey() Method in Java C chinmoy lenka Follow Improve Article Tags : Misc Java Java-Collections java-TreeMap Practice Tags : JavaJava-CollectionsMisc Similar Reads TreeMap in Java TreeMap is a part of the Java Collection Framework. 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