Java LongStream max() Method

The max() method in Java, part of the java.util.stream.LongStream interface, is used to find the maximum element in the stream. This method is useful when you need to determine the highest value in a stream of long values.

Table of Contents

1. Introduction
2. max() Method Syntax
3. Understanding max()
4. Examples
   • Basic Usage
   • Using max() with Filtered Streams
5. Real-World Use Case
6. Conclusion

Introduction

The max() method is a terminal operation that returns an OptionalLong describing the maximum element of the stream, or an empty OptionalLong if the stream is empty. This method is particularly useful for finding the highest value in a stream of long values.

max() Method Syntax

The syntax for the max() method is as follows:

OptionalLong max()

Parameters:

• This method does not take any parameters.

Returns:

• An OptionalLong describing the maximum element of the stream, or an empty OptionalLong if the stream is empty.

Throws:

• This method does not throw any exceptions.

Understanding max()

The max() method processes each element of the stream to determine the maximum value. If the stream is empty, it returns an empty OptionalLong. If the stream contains elements, it returns an OptionalLong containing the maximum value.

Examples

Basic Usage

To demonstrate the basic usage of max(), we will create a LongStream and use max() to find the maximum element.

Example

import java.util.OptionalLong;
import java.util.stream.LongStream;

public class MaxExample {
    public static void main(String[] args) {
        LongStream stream = LongStream.of(1L, 2L, 3L, 4L, 5L);

        // Use max() to find the maximum element
        OptionalLong maxElement = stream.max();

        // Print the maximum element if present
        maxElement.ifPresent(System.out::println);
    }
}

Output:

5

Using max() with Filtered Streams

This example shows how to use max() in combination with filtering to find the maximum value among elements that match a specific condition.

Example

import java.util.OptionalLong;
import java.util.stream.LongStream;

public class MaxWithFilterExample {
    public static void main(String[] args) {
        LongStream stream = LongStream.of(10L, 20L, 30L, 40L, 50L);

        // Use max() to find the maximum element greater than 25
        OptionalLong maxElement = stream.filter(n -> n > 25).max();

        // Print the maximum element if present
        maxElement.ifPresent(System.out::println);
    }
}

Output:

50

Real-World Use Case

Finding the Maximum Transaction Amount

In real-world applications, the max() method can be used to find the highest transaction amount from a stream of transaction values.

Example

import java.util.OptionalLong;
import java.util.stream.LongStream;

public class MaxTransactionExample {
    public static void main(String[] args) {
        LongStream transactionAmounts = LongStream.of(1000L, 2000L, 1500L, 3000L, 2500L);

        // Use max() to find the highest transaction amount
        OptionalLong maxTransaction = transactionAmounts.max();

        // Print the highest transaction amount if present
        maxTransaction.ifPresent(amount -> System.out.println("Highest Transaction Amount: " + amount));
    }
}

Output:

Highest Transaction Amount: 3000

Conclusion

The LongStream.max() method is used to find the maximum element in the stream. This method is particularly useful for determining the highest value in a stream of long values. By understanding and using this method, you can efficiently manage and process streams of values in your Java applications, ensuring that the maximum value is correctly identified.