The Java programming language uses Unicode throughout. In an effort to integrate well with other locales, gcj allows .java files to be written using almost any encoding. gcj knows how to convert these encodings into its internal encoding at compile time.
You can use the --encoding=NAME option to specify an
encoding (of a particular character set) to use for source files. If
this is not specified, the default encoding comes from your current
locale. If your host system has insufficient locale support, then
gcj assumes the default encoding to be the ‘UTF-8’ encoding
of Unicode.
To implement --encoding, gcj simply uses the host
platform's iconv conversion routine. This means that in practice
gcj is limited by the capabilities of the host platform.
The names allowed for the argument --encoding vary from platform
to platform (since they are not standardized anywhere). However,
gcj implements the encoding named ‘UTF-8’ internally, so if
you choose to use this for your source files you can be assured that it
will work on every host.