package tutorialspoint.collections;

import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;

public class TreeMapDemo {

  public static void main(String args[]) {
    // Create a hash map
    SortedMap<String, Double> tm = new TreeMap<String, Double>();
    // Put elements to the map
    tm.put("Zara", new Double(3434.34));
    tm.put("Mahnaz", new Double(123.22));
    tm.put("Ayan", new Double(1378.00));
    tm.put("Daisy", new Double(99.22));
    tm.put("Qadir", new Double(-19.08));

    // Get a set of the entries
    Set<Entry<String, Double>> set = tm.entrySet();
    // Get an iterator
    Iterator<Entry<String, Double>> i = set.iterator();
    // Display elements
    while (i.hasNext()) {
      Entry<String, Double> me = i.next();
      System.out.print(me.getKey() + ": ");
      System.out.println(me.getValue());
    }
    System.out.println();
    // Deposit 1000 into Zara's account
    double balance = tm.get("Zara").doubleValue();
    tm.put("Zara", new Double(balance + 1000));
    System.out.println("Zara's new balance: " + tm.get("Zara"));
    System.out.println("firstKey: " + tm.firstKey());
    System.out.println("headMap: " + tm.headMap("Qadir"));
    System.out.println("lastKey: " + tm.lastKey());
    System.out.println("subMap: " + tm.subMap("Daisy", "Quadir"));
    System.out.println("tailMap: " + tm.tailMap("Mahnaz"));
  }
}

package tutorialspoint.collections;

import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;

public class TreeMapDemo {

  public static void main(String args[]) {
    // Create a hash map
    SortedMap<String, Double> tm = new TreeMap<String, Double>();
    // Put elements to the map
    tm.put("Zara", new Double(3434.34));
    tm.put("Mahnaz", new Double(123.22));
    tm.put("Ayan", new Double(1378.00));
    tm.put("Daisy", new Double(99.22));
    tm.put("Qadir", new Double(-19.08));

    // Get a set of the entries
    Set<Entry<String, Double>> set = tm.entrySet();
    // Get an iterator
    Iterator<Entry<String, Double>> i = set.iterator();
    // Display elements
    while (i.hasNext()) {
      Entry<String, Double> me = i.next();
      System.out.print(me.getKey() + ": ");
      System.out.println(me.getValue());
    }
    System.out.println();
    // Deposit 1000 into Zara's account
    double balance = tm.get("Zara").doubleValue();
    tm.put("Zara", new Double(balance + 1000));
    System.out.println("Zara's new balance: " + tm.get("Zara"));
    System.out.println("firstKey: " + tm.firstKey());
    System.out.println("headMap: " + tm.headMap("Qadir"));
    System.out.println("lastKey: " + tm.lastKey());
    System.out.println("subMap: " + tm.subMap("Daisy", "Quadir"));
    System.out.println("tailMap: " + tm.tailMap("Mahnaz"));
    System.out.println(tm);
  }
}

Print out the content of the TreeMap.