Java InvocationTargetException while calling private method

I have a private method with such a signature:

private void compressFilesForSend(List<File> files, File archiveFile)

and I want to invoke it in a test through reflection

Class[] parameterTypes = new Class[2];
        parameterTypes[0] = java.util.List.class;
        parameterTypes[1] = java.io.File.class;

        Method method = SendDB.class.getDeclaredMethod("compressFilesForSend",parameterTypes);
        method.setAccessible(true);
        method.invoke(files, archiveFile);

How can this method be invoked?