Make sure that there is a whitespace. It's "' '{3}" not "{3}". :)

doesnt work for me :/

3 spaces you could use " {3}" instead~

• means more than one however ? sign means if more ok if not ok doesnt matter

it checks whether there are more than one whitespace and splits

Great solution, using Streams as other solutions I think is overkill for this kata.
I suggest changing the type of result from String to StringBuilder to make it faster and less memory hungry for big Strings.

StringBuffer is way slower than StringBuilder, because it is synchronized. And if nowadays you see StringBuffer anywhere in single threaded code it is archaic (or poorly written) code.
BTW code from kata with +="" whould compile to StringBuilder concentrations, very inefficient ones however.

first ,U should add this code:

morseCode.isEmpty() return "";

second ,
StringBuffer result
result.append()

how this works? word.split("\s+")?

Finally the same solution I found is the top one! All of the other problems I solved had solutions by other people that were way better, lol. I did go with the StringBuilder as others have mentioned but the difference is kind of trivial. That would just be an efficiency upgraded needed when dealing with larger datasets.

StringBuilder is more efficient.

spoiler flags!