Reading /Dev/Input/Js0 from Java

I'm trying to read /dev/input/js0 from Java but I keep getting

java.io.IOException: Invalid argument
at java.io.FileInputStream.read0(Native Method)
at java.io.FileInputStream.read(FileInputStream.java:207)
at Test.main(Test.java:7)

My code is

import java.io.*;

final class Test {
    public static final void main(String[] args) {
            try {
                    FileInputStream in = new FileInputStream("/dev/input/js0");
                    System.out.println(in.read());
            } catch(IOException e) {
                    e.printStackTrace();
            }
    }
}

My end goal is to be able to read input from my controller but I can't even seem to read one byte. What am I doing wrong? My user does have read and write access to the file.