I'm learning how to compile and run java classes in terminal using the commands javac and java.  I have no problem compiling and running an individual class, however, when I put that class into a package and try to run it, I get "Error: Could not find or load main class (class name)".  

Currently, my directory structure is: `~/Desktop/OCA_Practice/cert` the name of the file I'm running is called `Test.java` and I've placed it in a package called `cert`.  Here is my very basic class:

`package cert;
public class Test {
	public static void main(String args[]) {
		System.out.println("This is a test.");

When I run the command `javac Test.java` in the cert directory, the class compiles successfully, however, when I try to run `java Test` after compiling, that's when I get the error. I've tried running my folder structure in addition to the class when I try to run the program, as in `java Desktop.OCA_Practice.cert.Test` and that didn't work. I've changed my package declaration inside my class to `Desktop.OCA_Practice_Probs.cert` and that didn't work either.

I've tried a large variety of different approaches with no success.  Have I written the package name wrong in my class file? I ran the command: `java -version` and it shows that I'm running `java version "1.8.0_25"` so I'm pretty sure my class path is set correctly.

Thanks in advance for any responses.