TreeMap size() Method in Java with Examples Last Updated : 29 Nov, 2021 Comments Improve Suggest changes Like Article Like Report size() method of TreeMap class is used to get the size of the map which refers to the number of the key-value pair or mappings in the Map. --> java.util package --> TreeMap class --> size() Method Syntax: Tree_Map.size() Return Value: The size of the map which also means the number of key-value pairs present in the map. Example 1: Mapping String Values to Integer Keys Java // Java Program to Illustrate size() Method // of TreeMap class // Importing required classes import java.util.*; // Main class public class GFG { // Main driver method public static void main(String[] args) { // Creating an empty TreeMap by // declaring object of Integer, string pairs TreeMap<Integer, String> tree_map = new TreeMap<Integer, String>(); // Mapping string values to int keys // using put() method 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 elements of TreeMap System.out.println("Initial Mappings are: " + tree_map); // Now displaying the size of this map // using size() method System.out.println("The size of the map is " + tree_map.size()); } } Output: Initial Mappings are: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You} The size of the map is 5 Example 2: Mapping Integer Values to String Keys Java // Java Program to Illustrate the size() method // of TreeMap class // Importing required classes import java.util.*; // Main class public class GFG { // Main driver method public static void main(String[] args) { // Creating an empty TreeMap by // declaring object of string, integer pairs TreeMap<String, Integer> tree_map = new TreeMap<String, Integer>(); // Mapping int values to string keys // using put() method 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); // Printing the elements of TreeMap System.out.println("Initial Mappings are: " + tree_map); // Printing the size of the map // using size() method System.out.println("The size of the map is " + tree_map.size()); } } Output: Initial Mappings are: {4=15, Geeks=20, Welcomes=25, You=30} The size of the map is 4 Note: The same operation can be performed with any type of Mappings with variation and combination of different data types. Comment More infoAdvertise with us Next Article TreeMap size() Method in Java with Examples C chinmoy lenka Follow Improve Article Tags : Misc Java Java-Collections Java - util package java-TreeMap +1 More Practice Tags : JavaJava-CollectionsMisc Similar Reads TreeMap in Java TreeMap is a part of the Java Collection Framework. It implements the Map and NavigableMap interface and extends the AbstractMap class. It stores key-value pairs in a sorted order based on the natural ordering of keys or a custom Comparator. It uses a Red-Black Tree for efficient operations (add, re 11 min read Java TreeMap clear() Method The clear() method is a built-in method of the TreeMap class in Java of the java.util package. This method is used to remove all key-value mappings from the TreeMap. And after invoking this method, the map becomes completely empty.This method is very useful when we want to reset the map or discard a 2 min read TreeMap clone() Method in Java with Examples In Java, clone() method of the TreeMap class is used to return a shallow copy of the mentioned treemap. It just creates a copy of the map. --> java.util Package --> TreeMap Class --> clone() Method Syntax: Tree_Map.clone() Parameters: The method does not take any parameters. Return Type: A 2 min read Java TreeMap containsKey() Method The containsKey() method in Java is used to check if a given key exists in a TreeMap. If the key is present in the map, it returns true, otherwise, it returns false. This method is very helpful when we need to verify whether a mapping exists before performing any operation on it.Syntax of TreeMap co 3 min read TreeMap containsValue() Method in Java With Examples In Java, containsValue() method of the TreeMap class is used to check whether a particular value is being mapped by any key in the TreeMap. It takes the value as a parameter and returns True if that value is mapped by any of the keys in the map. --> java.util Package --> TreeMap class --> c 3 min read TreeMap entrySet() Method in Java The java.util.TreeMap.entrySet() method in Java is used to create a set out of the same elements contained in the treemap. It basically returns a set view of the treemap or we can create a new set and store the map elements into them. 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