How to Use the `ifPresent` Method with Java 8 Streams

What is the purpose of the `ifPresent` method in Java 8 Streams and how do I use it?

Optional<String> optionalValue = Optional.of("Hello, World!");
optionalValue.ifPresent(value -> System.out.println(value));

In Java 8, the `ifPresent` method is a part of the `Optional` class, which is often used in conjunction with Streams to avoid null checks. This method allows you to execute a specific action if the value is present, effectively increasing code readability and reducing the risk of `NullPointerExceptions`.

Optional<String> optionalValue = Optional.ofNullable(getValue());
optionalValue.ifPresent(value -> System.out.println("Value is: " + value));

Causes

• Using `ifPresent` with an empty Optional won't execute the provided action.
• Misunderstanding the purpose of `Optional` can lead to improper usage.

Solutions

• Use `ifPresent` to handle cases where you want to act only if a value is present.
• Always check if your Optional contains a value before calling `ifPresent`.

Mistake: Using `ifPresent` without first checking if the Optional is non-empty.

Solution: Always ensure your value is wrapped in an Optional before calling `ifPresent`.

Mistake: Assuming `ifPresent` returns a value.

Solution: Understand that `ifPresent` is a void method meant for side effects, not return values.