The **`HashTable.put()` method** is used to insert key-value pairs in a `HashTable`.

It is present in the `HashTable` class inside the `java.util` package.

# 
## Parameters

The `HashTable.put()` method takes two parameters:
* **`key`**: The key for the value in the `HashTable`.
* **`value`**: The value for the key in the `HashTable`.


## Return value
The `HashTable.put()` method returns the following:
* **`key`**: The previous value if an existing key is passed.
* **`null`**: If a new pair is passed, then `null` is returned.

## Code
Let's look at the below code snippet to understand it better.

import java.util.*;
class Main
{
    public static void main(String[] args) 
    {
        Hashtable<Integer, String> h1 = new Hashtable<Integer, String>();

        h1.put(1, "Let's");
        h1.put(5, "see");
        h1.put(2, "Hashtable.contains()");
        h1.put(27, "method");
        h1.put(9, "in java.");

        System.out.println(h1);
    }
}

## Explanation


* In line 1, we imported the required package.
* In line 2, we made a `Main` class.
* In line 4, we made a `main` function.
* In line 6, we declared a `HashTable` consisting of `Integer` type keys and `String` type values.
* In lines 8 to 12, we inserted values in the `HashTable` by using the `Hashtable.put()` method.
* In line 14, we print the `HashTable`.

In this way, we can use the `HashTable.put()` method to insert key-value pairs in the `HashTable`.


What is the HashTable.put() method in Java?

The HashTable.put() method inserts key-value pairs in a HashTable and returns previous value or null for new pairs.