...

JVM will optimize it and place the length of the string as it is not changed during the iterations

Did the same functionality but more explicit

I smell StackOverFlow + Heap polution with huge amount of intermediate String object.
Differently will not be used in production.

overthinking

Yeah it would be great to have this feature
I end up increasing all the page font size
and it is not very convenient.
Also if there will be an option to
drag each window size (as in Repl for e.g)
It will be great.

You can see all available katas in
Kata section (from the left toolbar)
Choose Loop from Tags list and your
preferred language and start solving
the katas starting from Kyu 8 (easiest)

Wrote almost same solution but breaking
out from loop sooner

Nice I done almost the same but used
sb when read from array.

can be done in linear time
but with more code "noise"

It can be simplifed even more using constant space

You dont want to change the caller digits array
dont use !