Solved: java stream find specific element

stream find specific element In the world of programming, especially in Java, there are many scenarios where one might need to search for a specific element within a stream. In this article, we will discuss how to find a specific element within a stream using Java. We will walk you through the whole process – from providing a solution to the problem, and explaining the code in a step-by-step manner, along with discussing some related libraries and functions that can come in handy while working on similar problems.


Streams in Java are a powerful and expressive programming feature introduced in Java 8. They provide a concise way to express complex data manipulations and transformations on collections such as lists and sets. One common task when dealing with a collection of data is finding a specific element that matches certain criteria or conditions. In this article, we’ll look at how to accomplish this using Java streams.

import java.util.Arrays;
import java.util.List;
import java.util.Optional;

public class StreamFindElement {
  public static void main(String[] args) {
    List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);

    // Find the first even number
    Optional<Integer> firstEven =
                                .filter(x -> x % 2 == 0)

    firstEven.ifPresent(value -> System.out.println("First even number: " + value));

Finding an Element in Stream

  • Java stream provides methods on collections to perform operations like filtering, mapping and collecting results based on certain conditions.
  • The filter method is used to apply a condition to all elements in the stream and filter out those that meet the condition.
  • findFirst method is used to find the first element in the stream that matches the given condition.

Now, let’s break down the code step by step.

1. First, we create a list of integers: `List numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);`
2. Next, we use the stream() method on the list to create a stream of integers.
3. To find the first even number, we apply a filter on the stream using the `filter(x -> x % 2 == 0)` method.
4. After applying the filter, we call the findFirst() method to get an `Optional` object containing the first even number if available.
5. Finally, we use the ifPresent() method on the `Optional` to print the value if it exists.

Java Optional

  • Optional is a container object that can hold a value or be empty. It is used to avoid dealing with null values and NullPointerExceptions in your code.
  • The ifPresent() method takes a lambda or method reference to be executed only if the Optional contains a value.
  • Optional is particularly useful when working with streams because they represent both the presence and absence of a value found in a stream after processing.

In conclusion, we have successfully learned how to find a specific element in a Java stream using the filter and findFirst methods. Additionally, we have explored the use of the Optional class to avoid dealing with null values and NullPointerExceptions. Make sure to keep exploring more functionalities and libraries in Java to improve your skills and become an efficient stream programmer.

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