Why do I get NoClassDefFoundError: java/awt/Desktop?

Question

I\'m trying to open an URI with Swing that I get above error.

What is the reason and how can I fix it?

When I do it in console everything is OK but

Answer 1

Doc on NoClassDefFoundError

The searched-for class definition existed when the currently executing class was compiled, but the definition can no longer be found.

You do have some incorrect classloading happening. Mostly due to wrong class loader chaining.