TreeMap higherKey() method in Java with Examples
Last Updated :
08 Jun, 2021
The higherKey() method of java.util.TreeMap class is used to return the least key strictly greater than the given key, or null if there is no such key.
Syntax:
public K higherKey(K key)
Parameters: This method takes the key k as a parameter.
Return Value: This method returns the least key greater than key, or null if there is no such key.
Exception: This method throws the NullPointerException if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys.
Below are the examples to illustrate the higherKey() method
Example 1:
Java
import java.util.*;
public class GFG1 {
public static void main(String[] argv) throws Exception
{
try {
TreeMap<Integer, String>
treemap = new TreeMap<Integer, String>();
treemap.put(1, "One");
treemap.put(2, "Two");
treemap.put(3, "Three");
treemap.put(4, "Four");
treemap.put(5, "Five");
System.out.println("TreeMap: " + treemap);
int value = treemap.higherKey(3);
System.out.println("The higherKey value "
+ " for 3: " + value);
}
catch (NullPointerException e) {
System.out.println("Exception thrown : " + e);
}
}
}
|
Output:
TreeMap: {1=One, 2=Two, 3=Three, 4=Four, 5=Five}
The higherKey value for 3: 4
Example 2: For NullPointerException
Java
import java.util.*;
public class GFG1 {
public static void main(String[] argv) throws Exception
{
try {
TreeMap<Integer, String>
treemap = new TreeMap<Integer, String>();
treemap.put(1, "One");
treemap.put(2, "Two");
treemap.put(3, "Three");
treemap.put(4, "Four");
treemap.put(5, "Five");
System.out.println("TreeMap: " + treemap);
System.out.println("Trying to get higherKey"
+ " value for null");
int value = treemap.higherKey(null);
System.out.println("Value is: " + value);
}
catch (NullPointerException e) {
System.out.println("Exception thrown : " + e);
}
}
}
|
Output:
TreeMap: {1=One, 2=Two, 3=Three, 4=Four, 5=Five}
Trying to get higherKey value for null
Exception thrown : java.lang.NullPointerException
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