higherKey(K key) method

higherKey(K key): It returns the key whose key strictly greater than the given key, or null if there is no such key.
throws ClassCastException,  if specified key toKey is incompatible for TreeMap.
NullPointerException, if toKey is null and TreeMap uses natural ordering, or its comparator does not permit null keys. It returns null if TreeMap is empty.

K higherKey(K key)

import java.util.TreeMap;
class ExampleOfTreeMap
{
	public static void main(String arg[])
	{
		TreeMap<Integer, String> listOfNames = new TreeMap<Integer, String>();
		listOfNames.put(3, "C");
		listOfNames.put(1, "A");
		listOfNames.put(2, "D");
		listOfNames.put(6, "B");
		listOfNames.put(8, "B");
		
		System.out.println("Map :"+listOfNames.higherKey(3));		
	}
}

Output: Map :6