Some characters cannot be stored AS IS on the properties file, it will have to entered using Unicode escape characters:
The default encoding for property files is ISO-8859-1
also known as Latin-1
characters. All non-Latin-1 characters must then be entered using Unicode escape characters.
Example, consider the following example using a french sentence:
#property file example:
sentence.french=Son père est allé à l'hôtel.
There are certain accents that are not part of the Latin-1 character set. Therefore, escaping it to its Unicode escape characters, we get:
#property file example:
sentence.french=Son p\u00e8re est all\u00e9 \u00e0 h\u00f4tel.
I hope this helps.