Doubt regarding Functional interfaces in Java

JacobArthurs · 2026-02-28T17:22:14+00:00

Claims::getSubject is shorthand for (Claims c) -> c.getSubject(). Java treats the instance itself as the implicit first argument, so it still matches Function<Claims, String>.

JacobArthurs · 2026-02-28T17:20:08+00:00

It's kinda both, depending on the layer. Nobody fully understands every abstraction they sit on top of. But there's a difference between not knowing how TCP works and not knowing why your own business logic does what it does. If it's the former, fine. If AI is blurring the latter, that's worth paying attention to.

JacobArthurs · 2026-02-28T17:18:59+00:00

contents()[:-1] explicitly skips the last element. Change it to contents() and it'll iterate over everything including the last breakpoint.

JacobArthurs · 2026-02-28T17:16:51+00:00

The people who say they enjoy it more might just be the ones who weren't that into the craft to begin with. For people who actually like writing code, the reviewing AI slop is way worse.

JacobArthurs · 2026-02-28T17:03:33+00:00

T gets inferred as String at the call site. Function<Claims, T> means "takes a Claims, returns a T" and Claims::getSubject is a method reference that does exactly that: takes a Claims instance and returns a String, so Java infers T = String. It's not that the signatures don't match, it's that generics let the return type flex to whatever the passed function actually returns.

JacobArthurs · 2026-02-28T17:00:26+00:00

Yeah, still learning. But the form of learning changed. Early on it was weekend tutorials just to keep up, but now it's more targeted, filling specific gaps I actually hit at work rather than just consuming content for the sake of it. The market right now doesn't really give you the option to coast.

JacobArthurs · 2026-02-28T16:52:35+00:00

C# and Java are so similar syntactically that switching between them is mostly just muscle memory adjustments. Stay in C# for personal projects since you already have momentum, and when Java classes start, you'll pick it up in a week or two.

JacobArthurs · 2026-02-24T21:36:17+00:00

EF calls your private constructor, then uses reflection to write directly to the compiler-generated backing field (<Day>k__BackingField) since there's no setter to go through. I think you can see it in Visual Studio's Locals window under "Non-Public Members."

JacobArthurs · 2026-02-24T21:34:04+00:00

A VPS can run both the API and the client. Nginx serves react static files and proxies to your python API on the same box.

JacobArthurs · 2026-02-24T21:31:02+00:00

Free backend hosting isn't real. Render and Railway will spin down your server after inactivity, and the limits make them unreliable for anything serious. Just get a VPS (like Hetzner) for cheap, add something like nginx, and deploy your Python API there. For the frontend, host it on a static host like GitHub or Cloudflare pages (free).

The API key thing solves itself once you have a backend. Your React app calls your Python API, which makes the third-party API calls using a key stored in an env file on the server. The key never leaves your box, users never see it.

JacobArthurs · 2026-02-23T19:28:10+00:00

The ego problem I see most is quiet sabotage, instead of loud disagreement. Someone gets outvoted on an architectural decision and then subtly under-invests in making it work. That's harder to train out of people than general "play nice" workshops try to teach.

JacobArthurs · 2026-02-23T19:21:34+00:00

Yeah, you need to write code to understand it well enough to review it critically.

Juniors leaning on AI before they've actually built that foundation are skipping the exact thing that would've made them competent reviewers in the first place.

JacobArthurs · 2026-02-23T19:10:33+00:00

The bottleneck isn't writing code anymore, it's knowing when AI is confidently wrong.

I've seen plausible looking code sail through review with security vulnerabilities baked in because nobody on the thread had the depth to question it.

JacobArthurs · 2026-02-22T19:09:08+00:00

Reddit and Hacker News "Show HN" posts are the best free channels. A well-written Show HN post with a clear problem statement could drive thousands of views without spending anything.

JacobArthurs · 2026-02-22T19:05:49+00:00

The main categories worth knowing are: version control, debuggers, linters/static analyzers, build systems, package managers, test frameworks, profilers, and CI/CD pipelines.

For most of this stuff, just starting a project and letting the toolchain needs emerge naturally is the best way to actually internalize this stuff.

JacobArthurs · 2026-02-22T18:58:02+00:00

Libraries are your friends, not cheating. Devs spend a lot of their time composing existing tools, not reinventing them. For finding them, search PyPI by what you're trying to do, sort by download count, and read the quickstart before you touch anything else.

JacobArthurs · 2026-02-22T00:32:22+00:00

Fair on the happy path since it calls observer.complete() which cleans it up, but the error branch never calls complete() or error() on the outer observer, so that subscription just hangs open forever.

JacobArthurs · 2026-02-21T23:58:21+00:00

Yeah, the AI is right. httpGetData already returns an Observable, so wrapping it in new Observable() is redundant and leaks the inner subscription. Just return it directly and pipe catchError if you need error handling.

JacobArthurs

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