versions2Java7Features

1package pkg2versions;2 3/*4 * versions2Java7Features.java  (2011)  "Project Coin"5 * ------------------------------------------6 * FEATURES & WHY:7 *  - try-with-resources : auto-close resources, less boilerplate, no leaks.8 *  - Diamond operator <> : infer generic type on the right side.9 *  - Strings in switch  : cleaner branching on strings.10 *  - Multi-catch        : handle multiple exception types in one block.11 *  - Numeric underscores: readable literals (1_000_000).12 *  - Binary literals    : 0b1010.13 */14import java.util.*;15 16public class versions2Java7Features {17 18    static class Resource implements AutoCloseable {19        public void close() { System.out.println("resource closed"); }20        void doWork() { System.out.println("working"); }21    }22 23    public static void main(String[] args) {24        // Diamond operator: the compiler fills in <String, List<Integer>>25        Map<String, List<Integer>> map = new HashMap<>();26        List<Integer> numbers = new ArrayList<>();27        numbers.add(1);28        map.put("a", numbers);29        System.out.println("diamond map: " + map);30 31        // try-with-resources32        try (Resource r = new Resource()) {33            r.doWork();34        }35 36        // Strings in switch37        String cmd = "start";38        switch (cmd) {39            case "start":40                System.out.println("starting...");41                break;42            case "stop":43                System.out.println("stopping...");44                break;45            default:46                System.out.println("unknown");47        }48 49        // Multi-catch50        try {51            if (cmd.equals("start")) throw new IllegalStateException("boom");52        } catch (IllegalStateException | IllegalArgumentException e) {53            System.out.println("multi-catch: " + e.getMessage());54        }55 56        // Numeric underscores + binary literals57        int million = 1_000_000;58        int bits = 0b1010_1010;59        System.out.println("million=" + million + " binary=" + bits);60    }61}