nice approach

https://docs.oracle.com/javase/8/docs/api/java/util/List.html#toArray-T:A-

Why is 'new String[0]' passed in as parameter to the toArray method. What does it even mean? Thanks in advance.

Because at that point index i+1 is same as string length.

And exception is not thrown by substring unless index is greater than string length

Refer: https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#substring(int)

Can someone explain how when the i gets to the last letter (str.length -1) there is not an out of bounds exception caused by the str.substring(i+1) ?

Compare:

1. "if ch is blank then skip", VS.
2. "if ch is not blank then do something"

Personally, I find option 1 is more natural way to describe the alogrithm. YMMV.

Is the use of the keyword "continue" better than using brackets in this case?