Java的隐藏功能

public static void printNumbers(int... numbers) {
    for (int number : numbers) {
        System.out.println(number);
    }
}

Integer a = 1;
int b = a;

int max = (a > b) ? a : b;

for (String str : arrayOfStrings) {
    System.out.println(str);
}

import static java.lang.Math.PI;

public class Circle {
    double radius = 5;
    double area = PI * radius * radius;
}