The Eclipse compiler doesn't seem to honour the -encoding flag, although it supports it. With javac, it works just fine. Background: I with Linux work in a team of windows users. Sometimes it happens, that german umlauts show up in the code. Because my system encoding is UTF-8 while the Windows users use cp-1252, this will lead to illegal characters on my machine. I remove such characters manually whenever I touch such a file, but for being able to compile without going through all the files, I pass the compiler -encoding windows-1252. The Eclipse compiler (both embedded and external) still complains about illegal characters in the source files.