private void testConnection() throws IOException {
        // For now, just test basic connectivity to RPC endpoint
        try (java.net.Socket socket = new java.net.Socket()) {
            socket.connect(new java.net.InetSocketAddress(serverAddress, WITNESS_RPC_PORT), WITNESS_RPC_TIMEOUT_MS);
        } catch (IOException e) {
            throw new IOException("Cannot connect to RPC endpoint at " + serverAddress.getHostAddress() + ":" + WITNESS_RPC_PORT, e);