Input: Stream = {“Geek_First”, “Geek_2”, “Geek_3”, “Geek_4”, “Geek_Last”}
Output: Geek_First

Input: Stream = {1, 2, 3, 4, 5, 6, 7}
Output: 1

There are many methods to the find first elements in a Stream:

1. Using Stream.reduce() Method: 
   The reduce technique works on two elements inside the movement and returns the detail as per the desired circumstance. consequently this method may be used to reduce the stream so that it consists of handiest the first element.

Approach:

• Get the circulate of elements wherein the first element is to be lower back.
• To get the first element, you could use the reduce() approach to disregard the second element, again and again, till there is no second element.

Stream.reduce((first, second) -> first)

• This reduces the set of factors in a movement to a single detail, that's first.
  
• consequently the simplest unmarried element will remain within the move that is the primary detail.

Below is the implementation of the above approach:

Example:

// Java program to find first
// element of a Stream in Java

import java.util.*;
import java.util.stream.*;

public class GFG {

	// Function to find the
	// first_elements in a Stream
	public static  T
	firstElementInStream(Stream stream)
	{
		T first_element
			= stream

				// reduce() method reduces the Stream
				// to a single element, which is first.
				.reduce((first, second) -> first)

				// if stream is empty
				// null is returned
				.orElse(null);

		return first_element;
	}

	// Driver code
	public static void main(String[] args)
	{

		Stream stream
			= Stream.of("Geek_First", "Geek_2",
						"Geek_3", "Geek_4",
						"Geek_Last");

		// Print the first element of a Stream
		System.out.println(
			"First Element: "
			+ firstElementInStream(stream));
	}
}

Output:

First Element: Geek_First

2. Using Stream findFirst() Method:  

Stream.findFirst()

• This will return the first element of the stream.

Below is the implementation of the above approach:

Example:

// Java program to find first
// element of a Stream in Java

import java.util.*;
import java.util.stream.*;

public class GFG {

	// Function to find the
	// first_elements in a Stream
	public static  T
	firstElementInStream(Stream stream)
	{
		T first_element
			= stream

				// findFirst() method returns
				// the first element of stream
				.findFirst()

				// if stream is empty
				// null is returned
				.orElse(null);

		return first_element;
	}

	// Driver code
	public static void main(String[] args)
	{

		Stream stream
			= Stream.of("Geek_First", "Geek_2",
						"Geek_3", "Geek_4",
						"Geek_Last");

		// Print the first element of a Stream
		System.out.println(
			"First Element: "
			+ firstElementInStream(stream));
	}
}

Output:

First Element: Geek_First