Why is '\117' a valid character literal in Java? [duplicate]

Question

I've seen this char defined as char ch = '\117'

What kind of representation is '\117' in?

I know escaped-sequence is '\n', for instance, or unicode is `\udddd', where d is a single hex digit, but I've never seen such thing as '\117' in my entire life! Surprisingly, it does compile! (And the output is O)

Answer 1

This is the octal representation for ascii. You can see lots more values of it here: http://donsnotes.com/tech/charsets/ascii.html

Answer 2

It's in octal, a holdover from C/C++.