Java TreeMap clear() Method Last Updated : 16 May, 2025 Comments Improve Suggest changes Like Article Like Report 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 all the existing entries without creating a new instance.Syntax of TreeMap clear() MethodtreeMap.clear();Parameters: This method does not accept any parameters.Return Value: This method does not return any value. It only removes all the entries from the map.Examples of TreeMap clear() MethodExample 1: In this example, we are going to create a TreeMap with Integer keys and String values and then clear it using the clear() method. Java // Java program to demonstrate TreeMap clear() method import java.util.TreeMap; public class Geeks { public static void main(String[] args) { // Create a TreeMap with Integer keys TreeMap<Integer, String> tm = new TreeMap<>(); // Add key-value pairs tm.put(10, "Geeks"); tm.put(15, "4"); tm.put(20, "Geeks"); tm.put(25, "Welcomes"); tm.put(30, "You"); System.out.println("Initial Mappings are: " + tm); // Clear the TreeMap tm.clear(); System.out.println("TreeMap after clear(): " + tm); } } OutputInitial Mappings are: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You} TreeMap after clear(): {} Explanation: Here, we have added entries to the map then we use the clear() method to remove all mappings. Then the TreeMap becomes empty.Example 2: In this example, we are using a TreeMap where keys are of type String and values are of type Integer. Java // Java program to demonstrate TreeMap clear() method import java.util.TreeMap; public class Geeks { public static void main(String[] args) { // Create a TreeMap with String keys TreeMap<String, Integer> tm = new TreeMap<>(); // Add key-value pairs tm.put("Geeks", 10); tm.put("4", 15); tm.put("Geeks", 20); tm.put("Welcomes", 25); tm.put("You", 30); System.out.println("Initial Mappings are: " + tm); // Clear the TreeMap tm.clear(); System.out.println("TreeMap after clear(): " + tm); } } OutputInitial Mappings are: {4=15, Geeks=20, Welcomes=25, You=30} TreeMap after clear(): {} Explanation: Here also the clear() method deletes all mappings from the map. Important Points: The clear() method is used to remove all mappings from a TreeMap.This method does not return any value.After clearing, the map size becomes zero.This method works with all combinations of key-value types i.e., Integer, String, etc.This method is very useful when reusing the same map instance in different logic blocks. Comment More infoAdvertise with us Next Article TreeMap clone() Method in Java with Examples C chinmoy lenka Follow Improve Article Tags : Java Java-Collections Java - util package java-TreeMap Practice Tags : JavaJava-Collections 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. Syntax: tree_map.entrySet() Parameters: The method does not take 2 min read TreeMap firstEntry() and firstKey() Method in Java with Examples There are two variants of first() in Java.util.TreeMap, both are discussed in this article. Method 1: firstEntry() It returns a key-value mapping associated with the least key in this map, or null if the map is empty. Syntax: public Map.Entry firstEntry() Return Type: An entry with the least key and 3 min read Java TreeMap get() Method The get() method of the TreeMap class in Java is used to retrieve or fetch the value mapped by a particular key mentioned in the parameter. If the key does not exist in the map, the method returns null.Syntax of TreeMap get() MethodtreeMap.get(Object key)Parameter: key: The method takes one paramete 2 min read TreeMap headMap() Method in Java The java.util.TreeMap.headMap(key_point) method of TreeMap class is used to get all the pairs or portion of the map strictly less than the parameter key_value. The mentioned parameter is excluded from the newly prepared treemap. Since the set is backed by the map, so any changes to the map are refle 3 min read TreeMap keySet() Method in Java with Examples In Java, keySet() method of TreeMap class is present inside java.util package in Java is used to create a set out of the key elements contained in the treemap. It basically returns a set view of the keys or we can create a new set and store the key elements in them in ascending order. Since the set 3 min read Like