RFR: 1838: better error message when download fails

[Erik Joelsson]

On Thu, 16 Mar 2023 17:11:57 GMT, Zhao Song <zsong at openjdk.org> wrote:

> Sometimes, users may want to run jcheck locally before creating PRs. However, Oracle employees who are connected to the Oracle VPN and have not set the https_proxy environment variable may encounter a "connect exception" error. 
> In this patch, we will provide users with more information in the case of a "connect exception" error while running jcheck.

cli/src/main/java/org/openjdk/skara/cli/GitJCheck.java line 353:

> 351:                 System.err.println(String.format("error: exception thrown during jcheck: %s", e.getMessage()));
> 352:                 if (e.getMessage().equals("java.net.ConnectException")) {
> 353:                     System.err.println("If you are connected to Oracle's VPN, please set the https_proxy environment variable and try again");

Suggestion:

                    System.err.println("If you are behind a firewall without direct access to the internet, make sure to configure any required proxy server through the https_proxy environment variable and try again");

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PR Review Comment: https://git.openjdk.org/skara/pull/1486#discussion_r1139217687