The java.util.IdentityHashMap.clear() method in Java is used to clear and remove all of the elements or mappings from a specified map.
Syntax:
Identity_HashMap.clear()
Parameters: The method does not accept any parameters.
Return Value: The method does not return any value.
Below programs are used to illustrate the working of java.util.IdentityHashMap.clear() Method:
Program 1: Mapping String Values to Integer Keys.
// Java code to illustrate the clear() methodimport java.util.*;  public class Identity_Hash_Map_Demo {    public static void main(String[] args)    {          // Creating an empty IdentityHashMap        IdentityHashMap<Integer, String> identity_hash = new IdentityHashMap<Integer, String>();          // Mapping string values to int keys        identity_hash.put(10, "Geeks");        identity_hash.put(15, "4");        identity_hash.put(20, "Geeks");        identity_hash.put(25, "Welcomes");        identity_hash.put(30, "You");          // Displaying the IdentityHashMap        System.out.println("Initial Mappings are: "                           + identity_hash);          // Clearing the map using clear()        identity_hash.clear();          // Displaying the final IdentityHashMap        System.out.println("Final Map: "                           + identity_hash);    }} |
Output:
Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
Final Map: {}
Program 2: Mapping Integer Values to String Keys.
// Java code to illustrate the clear() methodimport java.util.*;  public class Identity_Hash_Map_Demo {    public static void main(String[] args)    {          // Creating an empty IdentityHashMap        Map<String, Integer> identity_hash = new IdentityHashMap<String, Integer>();          // Mapping int values to string keys        identity_hash.put("Geeks", 10);        identity_hash.put("4", 15);        identity_hash.put("Geeks", 20);        identity_hash.put("Welcomes", 25);        identity_hash.put("You", 30);          // Displaying the IdentityHashMap        System.out.println("Initial Mappings are: " + identity_hash);          // Clearing the map using clear()        identity_hash.clear();          // Displaying the final IdentityHashMap        System.out.println("Final Map: "                           + identity_hash);    }} |
Output:
Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
Final Map: {}
Note: The same operation can be performed with any type of Mapping with variation and combination of different data types.
