Fix the "Wrong magic number" error messageTag(s): Environment

The "magic number" is represented by the first few bytes of a given file. It is used to identified the file type.

For Java classes, the magic number is 0xCAFEBABE (you can verify this by viewing a class file with hexadecimal editor or the DOS Debug utility). This is used by the browser JVM as a quick check of whether the called file is really a Java class.

If the message is displayed and you are sure that you have uploaded a "real" class to web server then it's probably because the FTP download has been done in TEXT mode instead of BINARY so the resulting file on the server is corrupted.