# 
## Overview

A **`LinkedHashMap`** is the same as `HashMap`, except that the `LinkedHashMap` maintains the insertion order, while the `HashMap` does not. 

Internally, the `LinkedHashMap` uses the doubly-linked list to maintain the insertion order. 

---
> Read more about `LinkedHashMap` [here](https://docs.oracle.com/javase/8/docs/api/java/util/LinkedHashMap.html).

# 
#  What is the `containsKey` method in `LinkedHashMap`?

The **`containsKey` method** of `LinkedHashMap` is used to check if a value is mapped to the specified key.

## Syntax

---
```java
public boolean containsKey(Object key)
```
---

## Argument

The key to being checked for presence is passed as an argument. 

## Return value

This method returns `true` if the key has a mapping. Otherwise, `false` will be returned.

##
## Code

The below example shows how to use the `containsKey` method.

import java.util.LinkedHashMap;
class LinkedHashMapContainsKeyExample {
    public static void main( String args[] ) {
      LinkedHashMap<Integer, String> map = new LinkedHashMap<>();
      map.put(1, "one");
      map.put(2, "two");
      System.out.println("\nChecking if the key '1' has mapping: "+ map.containsKey(1));
      System.out.println("\nChecking if the key '3' has mapping: "+ map.containsKey(3));
    }
}

#   
## Explanation 

In the above code:

* In line 1, we import the `LinkedHashMap` class.

* In line 2, we create a `LinkedHashMap` object with the name `map`.

* In line 5 and 6, we use the `put` method to add two mappings (`{1=one, 2=two}`) to the `map` object.

* In line 7, we use the `containsKey` method to check if the `map` has a mapping for the key `1`. `true` is returned as a result because the map has a mapping for the key `1`.

* In line 8, we use the `containsKey` method to check if the `map` has a mapping for the key `3`. `true` is returned as a result because the map has a mapping for the key `3`.

What is the LinkedHashMap.containsKey method in Java?

The LinkedHashMap's containsKey method checks if a key has a mapping, returning true or false.

What is the LinkedHashMap.containsKey method in Java?

Overview

What is the containsKey method in LinkedHashMap?

Syntax

Argument

Return value

Code

Explanation

What is the `containsKey` method in `LinkedHashMap`?