}
        if (b == null || b.length == 0) {
            throw new IllegalArgumentException("Buffer array cannot be null or empty");
        }
        if (bsize <= 0) {
            throw new IllegalArgumentException("Buffer size must be positive");
        }

        try {
            if (isDirectory()) {
                // Ensure destination exists as directory

         * actual files has a smaller maxBufSize this could be
         * incorrect. To handle this properly it is necessary
         * to redirect the tree to the target server first before
         * establishing buffer size. These exists() calls facilitate
         * that.
         */
        resolveDfs(null);

        /* It is invalid for the source path to be a child of the destination
         * path or visa versa.