New String methods
Java 11 added useful `String` methods: `isBlank` (empty or only spaces), `strip` (trim that understands Unicode), `lines` (split into lines as a stream) and `repeat`.
HTTP Client
Java 11 made `java.net.http.HttpClient` a standard part of Java.
Files.readString and writeString
Java 11 added `Files.readString` and `Files.writeString` to read or write a whole text file in one line, with UTF-8 by default.
Predicate.not
`Predicate.not` (Java 11) reverses a condition so you can use it with a method reference, for example `filter(Predicate.not(String::isBlank))` instead of writing a lambda with `!`.
var in lambda parameters
Java 11 lets you write `var` for lambda parameters.
Run a single file without compiling
Java 11 can run a `.java` file directly with `java Hello.java`.