jConnect uses the JCONNECT_VERSION to determine the default character-set converter class to use.
For JCONNECT_VERSION = 2.0 or 3.0, the default is TruncationConverter. For JCONNECT_VERSION = 4.0 or later, the default is PureConverter.
You can also set the CHARSET_CONVERTER_CLASS connection property to specify which character-set converter you want jConnect to use. This is useful if you want to use a character-set converter other than the default for your jConnect version.
... props.put("CHARSET_CONVERTER_CLASS", "com.sybase.jdbc4.charset.TruncationConverter")