client.java

static final String alphabet = "0123456789ABCDE";

	public static void main(String[] args) throws UnknownHostException, IOException {
		System.setProperty("javax.net.ssl.trustStore", "C:\\path\\to\\java\\truststore.jks");
		System.setProperty("javax.net.ssl.trustStorePassword", "Password1");
		SSLSocketFactory factory = (SSLSocketFactory) SSLSocketFactory.getDefault();
		SSLSocket sslsocket = (SSLSocket) factory.createSocket("127.0.0.1", 7000);
		OutputStreamWriter writer = new OutputStreamWriter(sslsocket.getOutputStream(), "UTF-8");
		char[] buffer = new char[9];
		Random r = new Random();
		for (int i = 0; i < 9; i++) {
			buffer[i] = alphabet.charAt(r.nextInt(alphabet.length()));
		}
		writer.write(buffer);
		writer.close();
		sslsocket.close();
	}