1、不用spring boot的选择

name, age, dept

list

2、
lambda排序
List.sort(employee, (a, b) -> ((a.name.compareTo(b.name)) && (a.age.compareTo(b.age))));

class Example {
//include the parent class
private Helper helper;

public synchronized Helper getHelper() {
//create one object if null
if (helper == null) {
helper = new Helper();
}

return helper;
}
}

3、怎么让日期彻底immutable
final class ImmutableClass {
final String string;
private final Date date;

}

4、Java 8 并行排序，有个方法