The Java.util.EnumMap.containsKey(key) method is used to check whether a specified key mentioned in the parameter is present in this map or not.
Syntax:
boolean containsKey(Object key)
Parameter: The method accepts one parameter key which refer to the key to be verified.
Return Value: The method returns true if the key is present in the EnumMap otherwise it returns false.
Below programs illustrate the containsKey() method:
Program 1:
// Java program to demonstrate containsKey() methodimport java.util.*;  // An enum of gfg visitors is createdpublic enum gfg_visitors {    India,    United_States,    China,    Japan,    Canada};  class Enum_map {    public static void main(String[] args)    {          EnumMap<gfg_visitors, String> mp = new         EnumMap<gfg_visitors, String>(gfg_visitors.class);          // values are associated in mp        mp.put(gfg_visitors.India, "61.4%");        mp.put(gfg_visitors.United_States, "18.4%");        mp.put(gfg_visitors.China, "2.5%");        mp.put(gfg_visitors.Japan, "1.1%");        mp.put(gfg_visitors.Canada, "1.1%");          // Check if map contains gfg visitor from United_States        boolean ans = mp.containsKey(gfg_visitors.United_States);          // Prints the result        System.out.println("gfg_visitors from United States: " + ans);    }} |
Output:
gfg_visitors from United States: true
Program 2:
// Java program to demonstrate containsKey() methodimport java.util.*;  // An enum of gfg visitors is createdpublic enum gfg_visitors {    India,    United_States,    China,    Japan,    Canada,    Russia};  class Enum_map {    public static void main(String[] args)    {          EnumMap<gfg_visitors, String> mp = new         EnumMap<gfg_visitors, String>(gfg_visitors.class);          // values are associated in mp        mp.put(gfg_visitors.India, "61.4%");        mp.put(gfg_visitors.United_States, "18.4%");        mp.put(gfg_visitors.China, "2.5%");        mp.put(gfg_visitors.Japan, "1.1%");        mp.put(gfg_visitors.Canada, "1.1%");          // check if map contains gfg visitor from Russia        boolean ans = mp.containsKey(gfg_visitors.Russia);          // prints the result        System.out.println("gfg_visitors from Russia: " + ans);    }} |
Output:
gfg_visitors from Russia: false
