I am trying to accept all certificates, and/or accept self-signed certificates using Apache HTTPClient version 4.5 (tutorial link here)
I've been going through solutions to this problem from a bunch of posts on SO. So far none of them have worked.
I keep getting this error: Error while trying to execute request. javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake
Apache Docs:
- Apache v4.5 tutorial
 - SSL/TLS customization
 - Apache has a guide for version 3, but not version 4.
 
Related StackOverflow Questions - Here's some links of the solutions I've tried:
- Ignoring SSL certificate in Apache HttpClient 4.3
 - How to ignore SSL certificate errors in Apache HttpClient 4.0
 - Ignore SSL Certificate Errors with Java
 - Need to trust all the certificates during the development using Spring
 - How to handle invalid SSL certificates with Apache HttpClient?
 
Note that in all these examples I am also passing a cookie store and a proxy credentials provider that I defined earlier. These are working, I'm just trying to add SSL support.
Try #1
Create my own ssl context with SSLContextBuilder and trust all self signed strategies with TrustSelfSignedStrategy. 
SSLContextBuilder sshbuilder = new SSLContextBuilder();
sshbuilder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sshbuilder.build());
CloseableHttpClient httpclient = HttpClients.custom()
    .setDefaultCredentialsProvider(credsProvider)
    .setDefaultCookieStore(cookieStore)
    .setSSLSocketFactory(sslsf)
    .build();
RESULT: Didn't work. Got Error while trying to execute request. javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake
Try #2
Same as above, but add a PoolingHttpClientConnectionManager 
SSLContextBuilder builder = new SSLContextBuilder();
builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(builder.build(),SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create()
        .register("http", new PlainConnectionSocketFactory())
        .register("https", sslsf)
        .build();
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(registry);
cm.setMaxTotal(2000);//max connection
CloseableHttpClient httpclient = HttpClients.custom()
    .setDefaultCredentialsProvider(credsProvider)
    .setDefaultCookieStore(cookieStore)
    .setSSLSocketFactory(sslsf)
    .setConnectionManager(cm)
    .build();
RESULT: Didn't work. Got Error while trying to execute request. javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake
Try #3
Simply accept ALL certificates by overriding the TrustStrategy (this is not recommended)
SSLContextBuilder builder = new SSLContextBuilder();
builder.loadTrustMaterial(null, new TrustStrategy() {
    @Override
    public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        return true;
    }
});
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(builder.build(),
    SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
CloseableHttpClient httpclient = HttpClients.custom()
    .setDefaultCredentialsProvider(credsProvider)
    .setDefaultCookieStore(cookieStore)
    .setSSLSocketFactory(sslsf)
    .build();
RESULT: Didn't work. Got Error while trying to execute request. javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake
Try #4
I found something useful from this answer:
As of version 4.5 HttpClient disables SSLv3 protocol version by default
Here's the solution he gave:
SSLContext sslcontext = SSLContexts.createSystemDefault();
SSLConnectionSocketFactory sslConnectionSocketFactory = new SSLConnectionSocketFactory(
        sslcontext, new String[] { "TLSv1", "SSLv3" }, null,
        SSLConnectionSocketFactory.getDefaultHostnameVerifier());
Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
        .register("http", PlainConnectionSocketFactory.INSTANCE)
        .register("https", sslConnectionSocketFactory)
        .build();
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
httpclient = HttpClients.custom()
    .setDefaultCredentialsProvider(credsProvider)
    .setDefaultCookieStore(cookieStore)
    .setSSLSocketFactory(sslConnectionSocketFactory)
    .setConnectionManager(cm)
    .build();
RESULT: Didn't work. Got Error while trying to execute request. javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake