I'm wondering if it would make sense to do some low level or OS stuff(a project) using Java. Reason why I ask is because I would like to expand my knowledge in Java and I'm into doing stuff like file compressor, bulk file renamer, etc. Are there any examples out there that I can look at or play with? Or should I just be using C or C++ instead?
Thanks!
Low level OS stuff is not very related to Java; Java uses a lot of abstractions (and hence making it higher level). You can, however, use the Java language and VM to interact with lower level API's using Java Native Access.
The problem with "low level" is: what is low level? Do you want to execute assembly instructions? And then there is Java: completely platform independent. Using more lower level API's in Java means that you lose the independency from your platform (think of: OS or hardware).
You can, however, also learn more about Java bytecodes: this is also quite low level.
If you provide more information on your project, I can give you a more specific answer.
stuff like file compressor, bulk file renamer, etc.
I wouldn't consider that "low level or OS stuff".
In my book, "low level or OS stuff" means things like device drivers. For that kind of thing, Java is very badly suited because it runs in a VM and simply does not have access to the OS API and the hardware (well, unless you run a Java-based OS).
For the two examples you name, Java could work quite well, but you could also easily run into limitations that are hard or impossible to overcome: Java's filesystem API dictates what you can do, and if that's not enough, the only thing left is to call native (i.e. C/C++) code via JNI or Runtime.exec().
I'm wondering if it would make sense to do some low level or OS stuff(a project) using Java.
Generally speaking, no. The low-level stuff is either taken care of by the JVM (or the operating system) or is impossible to do in pure Java.
However, if you are really interested in this kind of stuff, wander across to the JNode project and take a look at the various student projects on offer. JNode is a complete operating system that boots and runs on a "bare-metal" PC and is implemented (almost) entirely in Java.