converting ß.cfg to upper case using toUpperCase() in java

Question

I am trying following code

String s1 = \"ß.cfg\";
System.out.println (s.toUpperCase());

output I am getting is SS.CFG since U

Answer 1

The documentation for toUpperCase( Locale ) explicitly states that this is what will happen:

Since case mappings are not always 1:1 char mappings, the resulting String may be a different length than the original String.

small letter sharp s -> two letters: SS