I am working on a service which will replace Unicode characters by characters of a reduced unicode charset. For example characters like öäü are replaced by oau

But Unicode characers with more than 2 Bytes make trouble, for example the letter L̥̄
It consists of three bytes.

That is my code to replace the characters:

for (int i = 0; i < sourceString.length(); i++) {
            String searchChar =sourceString.substring(i, i + 1);
            String replaceChar = charMap.get(searchChar);
            System.out.println ("Char: " + searchChar + " is getting replaced by " + replaceChar);
            targetString += replaceChar;
        }

That will output:

Char: L is getting replaced by L
Char: ̥  is getting replaced by null
Char: ̄  is getting replaced by null
Target: Lnullnull

Instead of substring I tried codePointAt, but the result was the same.

How can I handle that?