Since the JVM redirects stdio/stdout/stderr, you might try something like this:
String[] cmd = {"/bin/sh", "-c", "stty raw </dev/tty"};Runtime.getRuntime().exec(cmd);
Note that stty (usually) operates on stdin not stdout.
The stty command performs a set of ioctl operations on standard input. When you call exec, you are forking and execing a new process.
Your choices are either JNI or switching to a GUI-style Java app instead of a console. Heck, you could build your own 100% Java 'console'.