<dependency>
            <groupId>org.java-websocket</groupId>
            <artifactId>Java-WebSocket</artifactId>
            <version>1.4.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.30</version>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.6</version>
        </dependency>

<repository>
    <id>jitpack.io</id>
    <url>https://jitpack.io</url>
</repository>

<dependency>
    <groupId>com.github.CaliDog</groupId>
    <artifactId>certstream-java</artifactId>
    <version>0.3</version>
</dependency>

package example;

import com.google.gson.Gson;
import io.calidog.certstream.CertStream;

/**
 * Prints out Messages
 */
public class ExampleClient {

    /**
     * Main method
     * @param args unused
     */
    public static void main(String[] args)
    {
        //string version of the message
        CertStream.onMessageString(System.out::println);


        CertStream.onMessage(msg -> System.out.println(new Gson().toJson(msg)));
    }
}

{
    "message_type": "certificate_update",
    "data": {
        "update_type": "X509LogEntry",
        "leaf_cert": {
            "subject": {
                "aggregated": "/CN=e-zigarette-liquid-shop.de",
                "C": null,
                "ST": null,
                "L": null,
                "O": null,
                "OU": null,
                "CN": "e-zigarette-liquid-shop.de"
            },
            "extensions": {
                "keyUsage": "Digital Signature, Key Encipherment",
                "extendedKeyUsage": "TLS Web Server Authentication, TLS Web Client Authentication",
                "basicConstraints": "CA:FALSE",
                "subjectKeyIdentifier": "AC:4C:7B:3C:E9:C8:7F:CB:E2:7D:5D:64:F2:25:0C:89:C2:AE:F0:5E",
                "authorityKeyIdentifier": "keyid:A8:4A:6A:63:04:7D:DD:BA:E6:D1:39:B7:A6:45:65:EF:F3:A8:EC:A1\n",
                "authorityInfoAccess": "OCSP - URI:http://ocsp.int-x3.letsencrypt.org\nCA Issuers - URI:http://cert.int-x3.letsencrypt.org/\n",
                "subjectAltName": "DNS:e-zigarette-liquid-shop.de, DNS:www.e-zigarette-liquid-shop.de",
                "certificatePolicies": "Policy: 2.23.140.1.2.1\nPolicy: 1.3.6.1.4.1.44947.1.1.1\n  CPS: http://cps.letsencrypt.org\n  User Notice:\n    Explicit Text: This Certificate may only be relied upon by Relying Parties and only in accordance with the Certificate Policy found at https://letsencrypt.org/repository/\n"
            },
            "not_before": 1508123861.0,
            "not_after": 1515899861.0,
            "as_der": "::BASE64_DER_CERT::",
            "all_domains": [
                "e-zigarette-liquid-shop.de",
                "www.e-zigarette-liquid-shop.de"
            ]
        },
        "chain": [
            {
                "subject": {
                    "aggregated": "/C=US/O=Let's Encrypt/CN=Let's Encrypt Authority X3",
                    "C": "US",
                    "ST": null,
                    "L": null,
                    "O": "Let's Encrypt",
                    "OU": null,
                    "CN": "Let's Encrypt Authority X3"
                },
                "extensions": {
                    "basicConstraints": "CA:TRUE, pathlen:0",
                    "keyUsage": "Digital Signature, Certificate Sign, CRL Sign",
                    "authorityInfoAccess": "OCSP - URI:http://isrg.trustid.ocsp.identrust.com\nCA Issuers - URI:http://apps.identrust.com/roots/dstrootcax3.p7c\n",
                    "authorityKeyIdentifier": "keyid:C4:A7:B1:A4:7B:2C:71:FA:DB:E1:4B:90:75:FF:C4:15:60:85:89:10\n",
                    "certificatePolicies": "Policy: 2.23.140.1.2.1\nPolicy: 1.3.6.1.4.1.44947.1.1.1\n  CPS: http://cps.root-x1.letsencrypt.org\n",
                    "crlDistributionPoints": "\nFull Name:\n  URI:http://crl.identrust.com/DSTROOTCAX3CRL.crl\n",
                    "subjectKeyIdentifier": "A8:4A:6A:63:04:7D:DD:BA:E6:D1:39:B7:A6:45:65:EF:F3:A8:EC:A1"
                },
                "not_before": 1458232846.0,
                "not_after": 1615999246.0,
                "as_der": "::BASE64_DER_CERT::"
            },
            {
                "subject": {
                    "aggregated": "/O=Digital Signature Trust Co./CN=DST Root CA X3",
                    "C": null,
                    "ST": null,
                    "L": null,
                    "O": "Digital Signature Trust Co.",
                    "OU": null,
                    "CN": "DST Root CA X3"
                },
                "extensions": {
                    "basicConstraints": "CA:TRUE",
                    "keyUsage": "Certificate Sign, CRL Sign",
                    "subjectKeyIdentifier": "C4:A7:B1:A4:7B:2C:71:FA:DB:E1:4B:90:75:FF:C4:15:60:85:89:10"
                },
                "not_before": 970348339.0,
                "not_after": 1633010475.0,
                "as_der": "::BASE64_DER_CERT::"
            }
        ],
        "cert_index": 19587936,
        "seen": 1508483726.8601687,
        "source": {
            "url": "mammoth.ct.comodo.com",
            "name": "Comodo 'Mammoth' CT log"
        }
    }
}