New to Java

I have been using C/C++, now starting to learn Java, and downloaded and installed JavaSE and Netbeans on my work computer yesterday.

I stumbled across nio which appears to be my io of choice for a project I will be working on and decided to try a very small program. It starts with:
import java.io.*;
import java.nio.*;
import java.nio.channels.*;
<10 more lines snipped>

When I try to compile it from the command line using XP SP2 the compiler says that it cannot find java.nio but it does find java.io.
javac MyBuffer.java

Is this a CLASSPATH issue? I note that CLASSPATH was apparently set by Quicktime and does not point to the new java sdk install.

Thanks