"Protocols in Swift" was retired on May 31, 2020.

Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Introduction to Functional Programming Java's Functional Toolset Function Shapes

Why did the code still raise an exception if requireNonNull was supposed to "catch" the null case?

Maybe I'm not understanding this but why did the code still raise an exception? I thought the requireNonNull catches the NullPointerException and calls the CreateIssue function instead of the code actually executing and raising an exception?

1 Answer

Ah nevermind, answered my own question. basically requireNonNull is still programmed to raise an exception. It's one of the functional programming methods that does the checking if something returns Null for you instead of coding it yourself.

Basically it replaces this:

If (input == null) {
do.something();
throw new IllegalArgumentException("Null input!");
} else {
code.Execute();
}
Mark Sebeck
Mark Sebeck
Treehouse Moderator 37,905 Points

I changed your comment to an answer and made it the Best Answer.