Eclipse wrong Java properties UTF-8 encoding

Question

I have a JavaEE project, in which I use message properties files. The encoding of those file is set to UTF-8. In the file I use the german umlauts like ä,

Answer 1

see: a marker such as FFFD (REPLACEMENT CHARACTER) in http://unicode.org/faq/utf_bom.html

and see native2ascii --help

   -encoding encoding_name
          Specifies the name of the character encoding to be used by the conversion procedure. If this option is not present, then the
          default character encoding (as determined by the java.nio.charset.Charset.defaultCharset method) is used. The encoding_name
          string must be the name of a character encoding that is supported by the JRE. See Supported Encodings at
          http://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html

a case

$ file yourfile.properties
yourfile.properties : ISO-8859 text, with very long lines
$ native2ascii -encoding ISO-8859-1 yourfile.properties yourfile.properties