I am using java to read from a webpage using this code:

import java.net.*;
import java.io.*;

public class URLReader {
public static void main(String[] args)  throws Exception {

    URL oracle = new URL("http://www.example.com/");
    BufferedReader in = new BufferedReader(
    new InputStreamReader(oracle.openStream()));

    String inputLine;
    while ((inputLine = in.readLine()) != null)

When I run the code with eclipse on my windows pc it works fine, but when I try to run it on my raspberry pi, I get this error:

javax.net.ssl.SSLHandshakeException:     sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid     certification path to requested target

I think it means java doesn’t trust the website, but I can’t find a solution anywhere. Any help would be greatly appreciated.

  • If the website uses https:// then does it have a valid publicly signed certificate or something that's self-signed? Is the root ca cert installed on your RPi? Is the server certificate trusted? Have you looked at Certbot to get a free (no charge) publicly valid certificate?
    – Dougie
    Feb 3, 2019 at 21:34
  • Sorry if this is a noob question, but how would I go about installing the root ca cert on my pi? Feb 3, 2019 at 22:26
  • Your local Google must be broken. bounca.org/tutorials/install_root_certificate.html
    – Dougie
    Feb 4, 2019 at 10:13

1 Answer 1


I fixed the problem by updating java As described here:https://www.raspberrypi.org/forums/viewtopic.php?t=200232

  • We're looking for long answers that provide some explanation and context. Don't just give a one-line answer just with a link; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed or you risk to get down votes.
    – Ingo
    Feb 7, 2019 at 22:57

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