sample of java 7 and 8 new feature.

java8_java7.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        // java8
        lambda();
        methodReference();

        // java7
        switchString("つらぽよ");
        numUnderScore();
        binaryLiteral();
        diamondExpression();
        multiCatch();
        tryWithResources();
        try {
            safeReThrow();
        } catch (Exception e) {
        }
    }

    // java8
    public static void lambda(){
        List<Integer> list = Arrays.asList(10, 12, 8, 5);
        Collections.sort(list, (o1, o2) -> o2 - o1);
        System.out.println(list.toString());
    }

    interface Duck {
        public String gaaaaa();
    }

    private static void honk(Duck duck) {
        System.out.println(duck.gaaaaa());
    }

    static class Man {
        public String yes() {
            return "yes!!";
        }
    }

    public static void methodReference(){
        honk(new Man()::yes);
    }

    // java7
    public static void switchString(String str) {
        switch (str) {
        case "つらぽよ":
            System.out.println("(´・ω・`)");
            break;
        case "イヤーッ！":
            System.out.println("グワーッ！");
            break;
        }
    }

    public static void numUnderScore() {
        int n = 123_456_1222;
        System.out.println(n);
    }

    public static void binaryLiteral() {
        int n = 0b11110111;
        System.out.println(n);
    }

    public static void diamondExpression() {
        List<String> list = new ArrayList<>();
        list.add("moge");
    }

    public static void tryWithResources() {
        try (InputStream in = new FileInputStream("soge"); InputStreamReader isr = new InputStreamReader(in); BufferedReader br = new BufferedReader(isr);) {
            // 処理
            String line = null;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void multiCatch() {
        try {
            InputStream in = new FileInputStream("moge");
        } catch (IOException | NullPointerException e) {
            e.printStackTrace();
        }
    }

    public static void safeReThrow() {
        try {
            String a = null;
            a.toUpperCase();
        } catch (Exception e) {
            throw e;
        }
    }
}