<https://github.com/wiremock/wiremock/blob/2.35.0/src/main/java/com/github/tomakehurst/wiremock/http/HttpClientFactory.java>

ProxyResponseRenderer

import javax.net.ssl.*;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.security.KeyStore;

public class MutualAuthHttpClient {
    private static final String KEYSTORE_TYPE = "JKS";
    private static final String KEYSTORE_PASSWORD = "password";
    private static final String TRUSTSTORE_TYPE = "JKS";
    private static final String TRUSTSTORE_PASSWORD = "password";
    private static final String KEY_MANAGER_ALGORITHM = "SunX509";
    private static final String SSL_CONTEXT_PROTOCOL = "TLS";

    public static void main(String[] args) throws Exception {
        String endpointUrl = "endpoint";
        String keystoreFilePath = "path/to/keystore";
        String truststoreFilePath = "path/to/keystore";

        KeyStore keyStore = KeyStore.getInstance(KEYSTORE_TYPE);
        keyStore.load(new FileInputStream(keystoreFilePath), KEYSTORE_PASSWORD.toCharArray());
        KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KEY_MANAGER_ALGORITHM);
        keyManagerFactory.init(keyStore, KEYSTORE_PASSWORD.toCharArray());

        KeyStore trustStore = KeyStore.getInstance(TRUSTSTORE_TYPE);
        trustStore.load(new FileInputStream(truststoreFilePath), TRUSTSTORE_PASSWORD.toCharArray());
        TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(KEY_MANAGER_ALGORITHM);
        trustManagerFactory.init(trustStore);

        SSLContext sslContext = SSLContext.getInstance(SSL_CONTEXT_PROTOCOL);
        sslContext.init(keyManagerFactory.getKeyManagers(), trustManagerFactory.getTrustManagers(), null);

        HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());

        HttpsURLConnection.setDefaultHostnameVerifier((String hostname, SSLSession session) -> true);

        URL url = new URL(endpointUrl);
        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setDoOutput(true);

        
        DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream());
        outputStream.flush();
        outputStream.close();

        BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        System.out.println(response.toString());
    }
}

enableBrowserProxying(true)