HttpUtil: fix invalid URI

[mherwege]

Providing an invalid URI input was throwing an IllegalArgumentException from the underlying jetty library. This change properly catches it and throws an IOException instead, aligned with the error treatment in the rest of the method.

See also openhab/openhab-addons#18066

[holgerfriedrich]

@mherwege not a review yet, just a remark:
Since we are using Java 21 now, URL(string) ctors are anyway deprecated and need to be replaced by URI.create(...).toUrl().
I have not managed to do this yet, but already got into trouble by the different handling of exceptions. URL throws MalformedURLException, URI.create may throw NullPointerException or IllegalArgumentException.
So this sounds familiar.

Can url be null? Then method shouldUseProxy could be problematic as well, as it may call .matches on a null string if exclusions are given.

[mherwege]

Since we are using Java 21 now, URL(string) ctors are anyway deprecated and need to be replaced by URI.create(...).toUrl().

I don't think that is entirely what the documentation says. It says to replace it with URI.toUrl(). But to create the URI, new URI(String str) is still OK and the URI.create(String str) method documentation explicitely states that this convenience method should only be used when you are sure str is a well formed URI.
The issue I try to solve is that HttpClient.newRequest(String str) from Jetty expects a well formed URI as input, and it was called with a not checked URL. It is actually calling URI.create(url) internally. So I make sure it is a well formed URI before calling it. And indeed, that lead to the IllegalArgumentException.
I didn't find any direct use of the URL(String str) constructor in this class.

Can url be null?

As this is called from static public functions and never checked, I guess it could be. There are also no Null annotations. I will put in some checks for this.

Then method shouldUseProxy could be problematic as well, as it may call .matches on a null string if exclusions are given.

This will also be solved by checking for a null url before calling the executeUrlAndGetReponse method.

[mherwege]

I didn't find any direct use of the URL(String str) constructor in this class.

I didn't look carefully. Replaced now.

[mherwege]

@holgerfriedrich I created a separate PR to remove all uses of the URL constructor from core.

[holgerfriedrich]

LGTM, thanks!