Compile-time code generation for JSON serialization. Annotate `@Serializable` on a data class; `Json.encodeToString` and `Json.decodeFromString` are typed.
`Optional::stream` (Java 9+) bridges optionals into the Stream API — collect all the `Some` values from a list of optionals, drop the empties, in one pipeline.
Plain `string` can't represent SQL NULL. Use `sql.NullString` (and its siblings `NullInt64`, `NullBool`, etc.) for columns where NULL is a real value distinct from empty.
Rust's ownership model: passing a value transfers ownership (move); taking a `&value` lets you read without taking ownership; `&mut value` lets you modify without taking ownership. Only one mutable borrow OR many immutable borrows at a time.
Comments and reviews can also have Schema.org markup. The `Review` type appears under products in Google search results with star ratings; `Comment` is for general user feedback.
Modern dataclass essentials: immutable instances (frozen=True), tighter memory + faster attribute access (slots=True), and default_factory for mutable defaults so every instance gets its own list.
Parse the standard HTTP Link header (RFC 5988) into a relation → URL map. Lets you follow rel="next" pagination in APIs like GitHub without manually building URLs.
`strconv.Atoi` / `Itoa` for the common int<->string case; `ParseFloat`, `ParseBool`, `Quote` for everything else. Always handle the error — strings can be anything.
Use PHP's built-in FILTER_VALIDATE_EMAIL with the FILTER_FLAG_EMAIL_UNICODE flag for IDN domains, plus a length sanity check. Trust this over hand-rolled regex.
Map each element to a Stream, then concatenate all of them into one. Used everywhere from "all words from a list of sentences" to "all permissions from a list of roles".
Java 21's virtual threads are millions-of-them cheap — JVM multiplexes them onto a small carrier pool. Replaces async/reactive code for most I/O-bound workloads: just write blocking code that doesn't actually block a kernel thread.
Convert any string to a URL-safe slug using only stdlib. Normalizes Unicode (NFKD), strips combining marks, lowercases, replaces non-alphanumerics with a separator.
A single-arg method/extension can be called without dot or parens when marked `infix`. Lets you write DSL-style code like `5 shouldBe 5` or `key to value`.