If it’s in the same package use
InputStream is = Driver.class.getResourceAsStream("myconfig.txt");
The way you have it
InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("myconfig.txt");
It’s looking for the file in the root of the classpath. You could use
InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("com/me/myapp/myconfig.txt");
The rules for searching are explained in the javadoc of ClassLoader#getResource(String)
and the javadoc of Class#getResource(String)
.