import java.security.cert.Certificate;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
public class Main {
public static void main(String[] argv) throws Exception {
int port = 443;
String hostname = "hostname";
SSLSocketFactory factory = HttpsURLConnection.getDefaultSSLSocketFactory();
SSLSocket socket = (SSLSocket) factory.createSocket(hostname, port);
socket.startHandshake();
// Retrieve the server's certificate chain
Certificate[] serverCerts = socket.getSession().getPeerCertificates();
socket.close();
}
}