Java TreeMap lastEntry() Method

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Description

TheJava TreeMap lastEntry() method is used to return a key-value mapping associated with the greatest key in this map, or null if the map is empty.

Declaration

Following is the declaration for java.util.TreeMap.lastEntry() method.

public Map.Entry<K,V> lastEntry()

Parameters

NA

Return Value

The method call returns an entry with the greatest key, or null if this map is empty.

Exception

NA

Getting Last Entry from a TreeMap of Integer, Integer Pairs Example

The following example shows the usage of Java TreeMap lastEntry() method to get the mapping associated with the greatest key in the map. We've created a TreeMap object of Integer,Integer pairs. Then few entries are added, and using lastEntry() we're printing a value for the greatest key.

package com.tutorialspoint;

import java.util.TreeMap;

public class TreeMapDemo {
   public static void main(String[] args) {

      // creating tree map 
      TreeMap<Integer, Integer> treemap = new TreeMap<>();

      // populating tree map
      treemap.put(2, 2);
      treemap.put(1, 1);
      treemap.put(3, 3);
      treemap.put(6, 6);
      treemap.put(5, 5);

      // getting the value with greatest key      
      System.out.println("Checking last entry");
      System.out.println("Value is: "+ treemap.lastEntry());
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Checking last entry
Value is: 6=6

Getting Last Entry from a TreeMap of Integer, String Pairs Example

The following example shows the usage of Java TreeMap lastEntry() method to get the mapping associated with the greatest key in the map. We've created a TreeMap object of Integer,String pairs. Then few entries are added, and using lastEntry() we're printing a value for the greatest key.

package com.tutorialspoint;

import java.util.TreeMap;

public class TreeMapDemo {
   public static void main(String[] args) {

      // creating tree map 
      TreeMap<Integer, String> treemap = new TreeMap<>();

      // populating tree map
      treemap.put(2, "two");
      treemap.put(1, "one");
      treemap.put(3, "three");
      treemap.put(6, "six");
      treemap.put(5, "five");

      // getting the value with greatest key      
      System.out.println("Checking last entry");
      System.out.println("Value is: "+ treemap.lastEntry());
   }    
}

Output

Let us compile and run the above program, this will produce the following result.

Checking last entry
Value is: 6=six

Getting Last Entry from a TreeMap of Integer, Object Pairs Example

The following example shows the usage of Java TreeMap lastEntry() method to get the mapping associated with the greatest key in the map. We've created a TreeMap object of Integer,Student pairs. Then few entries are added, and using lastEntry() we're printing a value for the greatest key.

package com.tutorialspoint;

import java.util.TreeMap;

public class TreeMapDemo {
   public static void main(String[] args) {

      // creating tree map 
      TreeMap<Integer, Student> treemap = new TreeMap<>();

      // populating tree map
      treemap.put(2, new Student(2, "Robert"));
      treemap.put(1, new Student(1, "Julie"));  
      treemap.put(3, new Student(3, "Adam"));
      treemap.put(6, new Student(6, "Julia"));
      treemap.put(5, new Student(5, "Tom"));

      // getting the value with greatest key      
      System.out.println("Checking last entry");
      System.out.println("Value is: "+ treemap.lastEntry());
   }    
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
   @Override
   public boolean equals(Object obj) {
      if(obj == null) return false;
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
}

Output

Let us compile and run the above program, this will produce the following result.

Checking last entry
Value is: 6=[ 6, Julia ]