constructs a charset object from a string (charset “UTF-8”) => java.nio.charset.Charset

returns the default charset

(charset:default) => “UTF-8”

returns the list of available charset

(charset-list) => (“Big5” “Big5-HKSCS” … “x-windows-iso2022jp”)

checks if object is an input-stream

checks if object is an output-stream

checks that object is a reader

checks that object is a writer