Avoiding the "javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed" error

Please note: this post focuses on the standard Java https implementation.

The SSLHandshakeException is thrown by java when the host you are trying to contact doesn't have a valid SSL certificate for that hostname. Most of the time this is very useful, since it means something on that host is wrong (the certificate has expired, the machine you're contacting is not who it is pretending to be etc...). However, in development mode you often don't want to pay for a "real" certificate, signed by a CA (certificate authority) like Verisign. You will then use a self-signed certificate, which gets rejected by java. It's for these cases that we're going to build a workaround. Please note that you should probably not use this code in a production environment. If you do, there's no reason to use https, since you're bypassing its functionality and you might just as well stick to http.

The first thing we need to do is create a custom TrustManager for SSL. SSL uses a protocol called X.509.  We will build a TrustManager that trusts all servers:

X509TrustManager tm = new X509TrustManager() { 
  @Override
  public X509Certificate[] getAcceptedIssuers() { 
    return null; 
  }   
  @Override
  public void checkServerTrusted(X509Certificate[] paramArrayOfX509Certificate, String paramString) throws CertificateException {   }   
  @Override
  public void checkClientTrusted(X509Certificate[] paramArrayOfX509Certificate, String paramString) throws CertificateException { } 
};

As you can see, the checkXXXTrusted() methods throw Exceptions when something is wrong. We never throw an exception, effectively trusting all hosts.

The next thing we'll need to do is use this TrustManager on an SSLContext. An SSLContext is a factory class that is used to create socket factories, which in their turn create the actual ssl sockets used to communicate with the server. Here's how we do this:

SSLContext ctx = SSLContext.getInstance("TLS"); 
ctx.init(null, new TrustManager[] { tm }, null); 
SSLContext.setDefault(ctx);

There now remains one more thing to be done: set a custom HostnameVerifier. A HostnameVerifier is a class that makes sure the host you are contacting doesn't use a spoofed URL. We will again build a HostnameVerifier that trusts all hosts:

HttpsURLConnection conn = (HttpsURLConnection) new URL("https://serverAddress").openConnection(); 
conn.setHostnameVerifier(new HostnameVerifier() {   
 @Override
 public boolean verify(String paramString, SSLSession paramSSLSession) { 
  return true; 
 } 
});

Again, this HostnameVerifier will trust all hosts.
Putting all our code together, the final class will look like this:

public static void main(String[] args) throws NoSuchAlgorithmException, KeyManagementException, MalformedURLException, IOException { 
 X509TrustManager tm = new X509TrustManager() { 
  @Override
  public X509Certificate[] getAcceptedIssuers() { 
   return null; 
  }   
  @Override
  public void checkServerTrusted(X509Certificate[] paramArrayOfX509Certificate, String paramString) throws CertificateException {   }   
  @Override
  public void checkClientTrusted(X509Certificate[] paramArrayOfX509Certificate, String paramString) throws CertificateException { } 
 }; 
 SSLContext ctx = SSLContext.getInstance("TLS"); 
 ctx.init(null, new TrustManager[] { tm }, null); 
 SSLContext.setDefault(ctx);   
 HttpsURLConnection conn = (HttpsURLConnection) new URL("https://serverAddress").openConnection(); 
 conn.setHostnameVerifier(new HostnameVerifier() {   
  @Override
  public boolean verify(String paramString, SSLSession paramSSLSession) { 
   return true; 
  } 
 }); 
 conn.connect();   
}

One final note: I prefer the way the Apache HttpClient library handles this. In the HttpClient library you can make a clean separation between the ssl verification logic and the code that does the actual work. This allows you to easily remove the code in the production environment or to use a switch between the development and production environment. This is much harder in the plain java version, since the code is more entangled. See this post for how to do this with the Apache HttpClient.