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Java TreeMap put() Method with Example

TreeMap Class put() method: Here, we are going to learn about the put() method of TreeMap Class with its syntax and example.
Submitted by Preeti Jain, on February 29, 2020

TreeMap Class put() method

• put() method is available in java.util package.
• put() method is used to put the value linked with the given key element (key_ele) when no other value associated previously otherwise it replaces the old value element with the given value element (val_ele) for the given key element (key_ele) when any value associated previously.
• put() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• put() method does not throw an exception at the time of replacing the value element if exists in this TreeMap.

Syntax:

    public Value put(Key key_ele, Value val_ele);

Parameter(s):

• Key key_ele – represents the key element with which the given value element is to be linked.
• Value val_ele – represents the value element to be linked with the given key element (key_ele).

Return value:

The return type of the method is Value, it returns the old value linked with the given key element when exists otherwise it returns null when none value exists.

Example:

// Java program to demonstrate the example 
// of Value put(Key key_ele, Value val_ele)
// method of TreeMap 

import java.util.*;

public class PutOfTreeMap {
    public static void main(String[] args) {
        // Instantiates TreeMap
        TreeMap < Integer, String > tm = new TreeMap < Integer, String > ();

        // By using put() method is
        // to put the key-value pairs in
        // treemap tm
        tm.put(1, "C");
        tm.put(4, "C++");
        tm.put(3, "Java");
        tm.put(2, "Php");

        // Display TreeMap tm
        System.out.println("tm: " + tm);

        // By using put() method is to
        // replace the value "php" with
        // the new value "SFDC" at the 
        // given indices "2"
        tm.put(2, "SFDC");

        // Display updated TreeMap tm
        System.out.println("tm.put(2,SFDC): " + tm);
    }
}

Output

tm: {1=C, 2=Php, 3=Java, 4=C++}
tm.put(2,SFDC): {1=C, 2=SFDC, 3=Java, 4=C++}