Какие нововведения появились в Java 8 и JDK 8?

• Lambda Expressions
• Stream API
• Default Methods
• Optional Class
• Nashorn JavaScript Engine
• Date and Time API (JSR 310)
• New methods in Collections interface (e.g., forEach, removeIf)
• Concurrent Accumulators (e.g., LongAdder, DoubleAdder)
• Parallel Array Sorting

// Пример Lambda Expression
Runnable r = () -> System.out.println("Hello from Lambda!");

// Пример Stream API
List<String> list = Arrays.asList("a", "b", "c");
list.stream().filter(s -> s.startsWith("a")).forEach(System.out::println);

// Пример Default Method
interface MyInterface {
    void abstractMethod();
    default void defaultMethod() {
        System.out.println("Default implementation");
    }
}

// Пример Optional
Optional<String> optional = Optional.ofNullable("present");
optional.ifPresent(System.out::println);