Before this PR jar files that were accessed via a URLResource, would stay opened indefinitely, and thus prevent the file from being modified. This PR fixes this by closing the JarURLConnection that is opened when calling exists(), contentLength() or lastModified() on Resource.
Comment From: f-cramer
Is there any chance to get this into one of the next releases? Or might I be able to improve the pull request somehow to make it "mergable"?
Comment From: sbrannen
Hi @f-cramer,
We'd like to get a better understanding of your use case.
How are you obtaining the URLResource reference? Are you creating it yourself or getting an instance from a mechanism in Spring Framework?
Please note that the proposed changes to AbstractFileResolvingResource are likely at the wrong level, since that would then automatically apply to other subclasses such as ClassPathResource and ServletContextResource which is likely undesirable. In other words, such a change would likely need to be limited to URLResource or custom subclasses of URLResource.
Speaking of the latter, would it be an option for you to create a subclass of URLResource for your use case?
Comment From: f-cramer
Hey @sbrannen the PR was opened to provide a fix for a bug in Java 8, which somehow prevented a JarURLConnection from correctly closing the corresponding file handle after usage (sorry, its been some time). As I can not find the JDK bug report and the problem does no longer seem to be happening in JDK 17, I will close this PR