Most production Java runs on 21, and will move next to 29. That means four releases of changes arriving in one upgrade. Java 26 shipped HTTP/3 in the standard HTTP client, faster startup, a free garbage collector improvement, and the first warnings in the plan to make final fields truly final. Here is what helps you, what will break your reflection-heavy libraries, and how to reduce the risk of an upgrade you have not started.
Autoregressive decoding is slow because it's sequential and memory-bandwidth bound — the GPU spends its time hauling multi-gigabyte weight matrices out of HBM, not doing math. Speculative decoding exploits that: a small draft model guesses the next few tokens, the big model verifies them all in a single pass, and a clever accept/reject rule makes the output byte-for-byte identical to the big model alone. Here's the whole trick.
The classic Linux I/O model costs at least one system call per operation — and every syscall got materially more expensive after the Spectre/Meltdown mitigations. io_uring flips the model: two ring buffers shared between your app and the kernel, batching hundreds of operations into one syscall or, with a polling thread, zero. Here's the mechanism, why true async file I/O finally exists, and the honest security caveats that keep it off some production boxes.
Virtual threads make Java look like Go for concurrency — until you hit a synchronized block, a ThreadLocal hot path, or a pool you forgot to remove. A working engineer's guide to what actually changes and what to leave alone.
Why streaming an 8-second answer makes it feel fast even though it isn't, how to pick between long-poll, SSE, and WebSockets, and how to build a NestJS SSE endpoint that proxies a streaming LLM call — including the proxy-buffering, cancellation, and mid-stream-error gotchas that bite everyone the first time.
How resolving redundant API calls and leveraging caching transformed a sluggish billing generation process into a performant operation.