Test of java SSL / keystore / cert setup. Check the comment #1 for howto.

SSLPoke.java

import javax.net.ssl.SSLParameters;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import java.io.*;

public class SSLPoke {
    public static void main(String[] args) {
        if (args.length != 2) {
            System.out.println("Usage: "+SSLPoke.class.getName()+" <host> <port>");
            System.exit(1);
        }
        try {
            System.setProperty("javax.net.ssl.trustStore", "/etc/pki/java/cacerts");
            SSLSocketFactory sslsocketfactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
            SSLSocket sslsocket = (SSLSocket) sslsocketfactory.createSocket(args[0], Integer.parseInt(args[1]));

            SSLParameters sslparams = new SSLParameters();
            sslparams.setEndpointIdentificationAlgorithm("HTTPS");
            sslparams.setProtocols(new String[] { "TLSv1.2" });
            //sslparams.setCipherSuites(new String[] { "TLS_DHE_RSA_WITH_AES_128_CBC_SHA" });
            sslsocket.setSSLParameters(sslparams);

            InputStream in = sslsocket.getInputStream();
            OutputStream out = sslsocket.getOutputStream();

            // Write a test byte to get a reaction :)
            out.write(1);

            while (in.available() > 0) {
                System.out.print(in.read());
            }
            System.out.println("Successfully connected");

        } catch (Exception exception) {
            exception.printStackTrace();
            System.exit(1);
        }
    }
}

Added a line to test a specific keystore

Added params to set tls version and cipher suite(s)