The containsKey() method of java.util.concurrent.ConcurrentSkipListMap is an in-built function in Java which returns a true boolean value if the specified element is present in this map otherwise it returns false.
Syntax:
public boolean containsKey(Object ob)
Parameter: The function accepts a single mandatory parameter ob which specifies the key whose presence in this map is to be tested.
Return Value: The function returns true if this map contains a mapping for the specified key.
Below programs illustrate the above method:
Program 1:
// Java Program Demonstrate containsKey()// method of ConcurrentSkipListMap  import java.util.concurrent.*;  class GFG {    public static void main(String[] args)    {          // Initializing the map        ConcurrentSkipListMap<Integer, Integer>            mpp = new ConcurrentSkipListMap<Integer,                                            Integer>();          // Adding elements to this map        for (int i = 1; i <= 5; i++)            mpp.put(i, i);          // Checks if 9 is present in the map        if (mpp.containsKey(9))            System.out.println("9 is present"                               + " in the mpp.");        else            System.out.println("9 is not present"                               + " in the mpp.");    }} |
Program 2:
// Java Program Demonstrate containsKey()// method of ConcurrentSkipListMap  import java.util.concurrent.*;  class GFG {    public static void main(String[] args)    {          // Initializing the map        ConcurrentSkipListMap<Integer, Integer>            mpp = new ConcurrentSkipListMap<Integer,                                            Integer>();          // Adding elements to this map        for (int i = 1; i <= 5; i++)            mpp.put(i, i);          // Checks if 4 is present in the map        if (mpp.containsKey(4))            System.out.println("4 is present"                               + " in the mpp.");        else            System.out.println("4 is not present"                               + " in the mpp.");    }} |
