How can I handle errors in Java 8 Stream API?

How can I handle errors in Java 8 Stream API?

In Java 8 Stream API, you can handle errors by using try-catch blocks within the stream operations. For example, you can wrap your lambda expressions in a try-catch to manage exceptions.

Can you show me an example of that?

Sure! Here's a simple example:

List<String> numbers = Arrays.asList("1", "2", "a", "4");
List<Integer> result = numbers.stream()
    .map(num -> {
        try {
            return Integer.parseInt(num);
        } catch (NumberFormatException e) {
            return null; // Handle the error
        }
    })
    .filter(Objects::nonNull)
    .collect(Collectors.toList());

What happens to the invalid entries in this example?

In this example, invalid entries like "a" are caught by the exception handler and replaced with null. The subsequent filter(Objects::nonNull) call removes these null values from the final result.

Is there a way to log the errors instead of just ignoring them?

Yes, you can log the errors by adding a logging statement in the catch block. For example:

catch (NumberFormatException e) {
    System.err.println("Invalid number: " + num);
    return null;
}