1.容器初始化
老的寫法是這樣的

HashMap<String, String> map = new HashMap<String, String>();
map.put("name", "test");  
map.put("age", "20");

文藝寫法

//map初始化
HashMap<String, String> map = new HashMap<String, String>() {
    {
        map.put("name", "test");  
        map.put("age", "20"); 
    }
};

//List初始化
List<String> names = new ArrayList<String>() {
    {
        for (int i = 0; i < 10; i++) {
            add("A" + i);
        }
    }
};
//或者
List<String> list = ["item"];
Map<String, Integer> map = {"key" : 1};

當然，我其實推薦GUAVA

Map<String, Integer> left = ImmutableMap.of("a", 1, "b", 2, "c", 3);
//或者
Map<String, String> test = ImmutableMap.<String, String>builder()
    .put("k1", "v1")
    .put("k2", "v2")
    ...
    .build();