JAVA 容器初始化

使用双括号

HashMap codeStyle = new HashMap(){{
      put("java","easy");
      put("python","easy");
      put("c","hard");
}};

使用Guava

Map studentAge = ImmutableMap.of("Jim", 10, "Kate", 11, "Lucy", 9);

JDK 9

Map.of("Hello", 1, "World", 2); // 不可变集合

使用JDK8 stream

List list = Stream.of("TV", "MOBILE", "MOTOR").collect(Collectors.toList());
List set = Stream.of("TV", "MOBILE", "MOTOR").collect(Collectors.toSet());