Use the java.nio.charset.StandardCharsets.{ISO_8859_1,UTF_8} constants'
name() methods instead of hard-coding the strings.
Where possible, use method variants that take a Charset rather than
a String. This removes the need to catch UnsupportedEncodingException
in some cases.
Change-Id: I4ac1ba0a753de715e1f38ce631842f527b9e127c