The java.util.TreeMap.lastKey() is used to retrieve the last or the highest key present in the map.
Syntax:
tree_map.lastKey()
Parameters: The method does not take any parameters.
Return Value: The method returns the last key present in the map.
Exception: The method throws NoSuchElementException if the map is empty.
Below programs illustrate the working of java.util.TreeMap.lastKey() method:
Program 1:
// Java code to illustrate the lastKey() method import java.util.*;
public class Tree_Map_Demo {
public static void main(String[] args)
{
// Creating an empty TreeMap
TreeMap<Integer, String> tree_map = new TreeMap<Integer, String>();
// Mapping string values to int keys
tree_map.put( 10 , "Geeks" );
tree_map.put( 15 , "4" );
tree_map.put( 20 , "Geeks" );
tree_map.put( 25 , "Welcomes" );
tree_map.put( 30 , "You" );
// Displaying the TreeMap
System.out.println( "The Mappings are: " + tree_map);
// Displaying the lastKey of the map
System.out.println( "The last key is " + tree_map.lastKey());
}
} |
Output:
The Mappings are: {10=Geeks, 15=4, 20=Geeks, 25=Welcomes, 30=You} The last key is 30
Program 2:
// Java code to illustrate the lastKey() method import java.util.*;
public class Tree_Map_Demo {
public static void main(String[] args)
{
// Creating an empty TreeMap
TreeMap<String, Integer> tree_map = new TreeMap<String, Integer>();
// Mapping int values to string keys
tree_map.put( "Geeks" , 10 );
tree_map.put( "4" , 15 );
tree_map.put( "Geeks" , 20 );
tree_map.put( "Welcomes" , 25 );
tree_map.put( "You" , 30 );
// Displaying the TreeMap
System.out.println( "The Mappings are: " + tree_map);
// Displaying the lastKey of the map
System.out.println( "The last key is " + tree_map.lastKey());
}
} |
Output:
The Mappings are: {4=15, Geeks=20, Welcomes=25, You=30} The last key is You