A source code file is a stream of bytes. When bytes are converted to characters, some scheme is used to determine what character each byte's value represents.
By default, the compiler uses the "platform default encoding". Which is your problem, because this is different on different systems. On your computer, the default seems to be Cp1252 (a Microsoft standard, used by Windows in North America and Western Europe).
This causes problems, when code is worked on by teams in different countries. For example, sometimes I have worked with developers in Russian-speaking countries. In Russia, Windows uses Cp1251 (Windows Cyrillic). In '1252, the byte 0xe9 represents the character "é" (lowercase latin e-acute). But '1251, 0xe9 is "й" (lowercase cyrillic short-i).
So, you have two options.
1. Find out what encoding the files were saved with. The developers might know this, but possibly not. The default encoding can be found by:
2. Get them to save the files again, forcing the encoding to something like (as the ealier poster suggests) UTF-8.
String encodingName = System.getProperty("file.encoding");
Either way, you must choose the same encoding in your IDE/compiler.
Beware that, if there is Japanese text in the product, it might not show on your device, if your device is not a Japanese model.