When running an applet in Japanese mode, the encoding of HTML file is chosen to the SHIFT JIS code. Nevertheless, the template of HTML file is encoded to UTF-8 code. Therefore, the web browser cannot display the Japanese message written in the HTML file correctly.
This problem has been detected since BlueJ 2.5 in that version the UTF-8 encoding was selected. Before the BlueJ 2.5.x, BlueJ had been adopted the SHIFT JIS code. This problem occurs in both Windows version and Macintosh version.