Syntax error Remove the first entry of the TreeMap in Java

Remove the first entry of the TreeMap in Java

To remove the first entry of the TreeMap, use the pollFirstEntry() method.

Let us first create a TreeMap and add elements −

TreeMap<Integer,String> m = new TreeMap<Integer,String>();
m.put(1,"India");
m.put(2,"US");
m.put(3,"Australia");
m.put(4,"Netherlands");
m.put(5,"Canada");

Remove the first entry now −

m.pollFirstEntry()

The following is an example to remove the first entry of the TreeMap.

Example

 Live Demo

import java.util.*;
public class Demo {
   public static void main(String args[]) {
      TreeMap<Integer,String> m = new TreeMap<Integer,String>();
      m.put(1,"India");
      m.put(2,"US");
      m.put(3,"Australia");
      m.put(4,"Netherlands");
      m.put(5,"Canada");
      System.out.println("TreeMap Elements = "+m);
      System.out.println("Removing First Entry : "+m.pollFirstEntry());
      System.out.println("Updated TreeMap Elements = "+m);
   }
}

Output

TreeMap Elements = {1=India, 2=US, 3=Australia, 4=Netherlands, 5=Canada}
Removing First Entry = 1=India
Updated TreeMap Elements = {2=US, 3=Australia, 4=Netherlands, 5=Canada}
Updated on: 2019-07-30T22:30:24+05:30

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