[Solved] Accessing an external library

I can set up my ILibrarySet far enough that it downloads the library but I can't seem to access it. I know I'm making a simple error somewhere but I can't quite put my finger on it. Could someone please tell me where I've gone wrong?

public class CoreLibrarySet implements ILibrarySet
{
    private static String[] libraries = { "xstream-1.4.4.jar"};
    private static String[] checksums = { "488e9e4a47afc81d2b2dec3c3eb3a4d0f10fe105" };


    @Override
    public String[] getLibraries()
    {
        return libraries;
    }


    @Override
    public String[] getHashes()
    {
        return checksums;
    }


    @Override
    public String getRootURL()
    {
        return "https://nexus.codehaus.org/content/repositories/releases/com/thoughtworks/xstream/xstream/1.4.4/%s";
    }
}

Edit: Nevermind, I seemed to have solved it somehow.