#   
## Overview

The **`requireNonNullElseGet` method** is a static method of the `Objects` class in Java that works as follows:

* If the supplied object is `null`, then the return value is computed from the `get()` method of the `Supplier` interface passed to it as a parameter.
* If the supplied object is *not* `null`, then the object is returned as-is.


>This method was introduced in Java 8. 

To use the `requireNonNull` method, import the following module.

```
java.util.Objects
```

#  Method signature

```
public static <T> T requireNonNullElseGet(T obj, Supplier<? extends T> supplier)
```

##  
## Parameters  
* `T obj`: object.  
* `Supplier<? extends T> supplier`: supplier of the non-null object to return if the passed object is `null`.

#   
## Example 1

In the code below, `null` is sent to the method as the object. An empty list of `Object` is then returned.

import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.function.Supplier;

public class Main {
    public static void main(String[] args) {
        System.out.println(Objects.requireNonNullElseGet(null, (Supplier<List<Object>>) Collections::emptyList));
    }
}


#   
## Example 2

In the code below, a non-null object is passed to the method, and the method returns the passed object.

import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.function.Supplier;

public class Main {
    public static void main(String[] args) {
        String s = "hello";
        System.out.println(Objects.requireNonNullElseGet(s, (Supplier<List<Object>>) Collections::emptyList));
    }
}


What is Objects.requireNonNullElseGet in Java?

Validates non-null input, returning it or a supplier-generated value if null, introduced in Java 8.
