KNOX-3138 implemented try-with-resources for Closeables

[dk2k]

KNOX-3138 implemented try-with-resources for Closeables (prevents resource leaks)
Closeables need to be closed properly and the native way is try-with-resources.
I haven't executed any tests for one simple reason: if the changed code is buildable, I don't expect any issues (It's not the first time when I implement try-with-resources)
As you can see, all checks are green.

I wish I could provide more details.

[lmccay]

Hi @dk2k - Thank you for your contribution! While we wait for the checks to pass, can you please revisit the PR description to follow the template that we provide for contributions? That level of detail is important for reviews. Thanks again!

[lmccay]

KNOX-3138 implemented try-with-resources for Closeables (prevents resource leaks) Closeables need to be closed properly and the native way is try-with-resources. I haven't executed any tests for one simple reason: if the changed code is buildable, I don't expect any issues (It's not the first time when I implement try-with-resources) As you can see, all checks are green.

I wish I could provide more details.

@dk2k - I'd like to better understand your motivation for making this change. Did you encounter an issue with them not being closed? If so, have to tried this and observed it being addressed?

Otherwise, I'd like to understand how you determined that you wanted to make this change.

[dk2k]

@lmccay try-with-resources (TwR) was introduced exactly for these cases. If a closeable has a non-empty close() method, it should be called. Of course, you can call close() explicitly, but it's boilerplate code.
I found this issue with static analysis tool.
From my experience: if code is buildable after such changes, it means the changes are safe.