TLS Socket Client Handshaker in Kotlin with Java8 runtime defaults

SslSocketClient.kt

import java.io.IOException
import java.security.KeyManagementException
import java.security.NoSuchAlgorithmException
import java.security.Security
import java.security.cert.X509Certificate
import javax.net.ssl.SSLContext
import javax.net.ssl.SSLSocket
import javax.net.ssl.TrustManager
import javax.net.ssl.X509TrustManager

object SslSocketClient {
    private const val host = "host"
    private const val port = 443

    @JvmStatic
    @Throws(NoSuchAlgorithmException::class, IOException::class, KeyManagementException::class)
    fun main(args: Array<String>) {
        Security.setProperty("crypto.policy", "limited")
        System.setProperty("javax.net.debug", "ssl:handshake")
        System.setProperty("jdk.tls.namedGroups", "secp256r1, secp384r1, secp521r1, secp160k1")
        System.setProperty("javax.net.debug", "ssl:handshake")
        System.setProperty("jdk.tls.client.enableStatusRequestExtension", "false")
        System.setProperty("jsse.enableFFDHEExtension", "false")
        System.setProperty("jdk.tls.client.protocols", "TLSv1.1,TLSv1.2")
        
        val sslContext = SSLContext.getInstance("TLS")
        sslContext.init(null, arrayOf<TrustManager>(object : X509TrustManager {
            override fun checkClientTrusted(x509Certificates: Array<X509Certificate>, s: String) {
                println("Skip trust check for: " + x509Certificates[0])
            }

            override fun checkServerTrusted(x509Certificates: Array<X509Certificate>, s: String) {
                println("Skip trust check for: " + x509Certificates[0])
            }

            override fun getAcceptedIssuers(): Array<X509Certificate?> {
                return arrayOfNulls(0)
            }
        }), null)

        (sslContext.socketFactory.createSocket(host, port) as SSLSocket).use { sslSocket ->
            sslSocket.useClientMode = true
            sslSocket.addHandshakeCompletedListener {
                evt -> println("Handshake completed: ${evt.session.protocol} - ${evt.session.cipherSuite}, ${evt.socket}")
            }
            sslSocket.startHandshake()
        }
    }
}