Java TreeMap - descendingMap() Method
The java.util.TreeMap.descendingMap() method returns a reverse order view of the mappings contained in this map. The descending map is backed by this map, so changes to the map are reflected in the descending map, and vice-versa.
Syntax
public NavigableMap<K,V> descendingMap()
Here, K and V are the type of key and value respectively maintained by the container.
Parameters
No parameter is required.
Return Value
Returns a reverse order view of this map.
Exception
NA.
Example:
In the example below, the java.util.TreeMap.descendingMap() method returns a reverse order view of the mappings contained in the given map.
import java.util.*;
public class MyClass {
public static void main(String[] args) {
//creating a treemap
TreeMap<Integer, String> Map1 = new TreeMap<Integer, String>();
//populating Map1
Map1.put(102, "John");
Map1.put(103, "Marry");
Map1.put(101, "Kim");
Map1.put(104, "Jo");
Map1.put(105, "Sam");
//printing the Map1
System.out.println("Map1 contains: " + Map1);
//creating a reverse order view of mapping
NavigableMap<Integer, String> Map2 = Map1.descendingMap();
//printing the Map2
System.out.println("Map2 contains: " + Map2);
}
}
The output of the above code will be:
Map1 contains: {101=Kim, 102=John, 103=Marry, 104=Jo, 105=Sam}
Map2 contains: {105=Sam, 104=Jo, 103=Marry, 102=John, 101=Kim}
❮ Java.util - TreeMap
