jMimeMagic is a Java library for determining the MIME type of files or streams, this you can find on google i you search on jMimeMagic, but is this possible without using this jar file from jMimeMagic ???
So by "binary bytes" you mean that the bytes represent certain non-text file types? Well, some file types have a magic number -- the first few bytes are always some certain value that identifies the file. For example, the first four bytes of a Java class file are 0xCA 0xFE 0xBA 0xBE , and the first few bytes of a GIF image are 0x47 0x49 0x45. But not all file types have a magic number, which is why figuring out the type of a file from the bytes is sometimes tricky.
The web site Wotsit's Format is a repository of information about file formats: it will likely have all known information about whatever file formats you're interested in.