public static <T extends java/lang/Object & java/lang/Comparable<? super T>> T max(java.util.Collection<? extends T>);
  public static <T extends java/lang/Object> T max(java.util.Collection<? extends T>, java.util.Comparator<? super T>);

------解决方案--------------------

Java code


class StudentComparator implements Comparator<Student> {
    public int compare(Student o1, Student o2) {
    return (o1.age < o2.age ? -1 : (o1.age == o2.age ? 0 : 1));
    }
}

public class testSort {
    public static void main(String[] args) {
    Student stu1 = new Student("zhangsan", 18);
    Student stu2 = new Student("lisi", 20);
    Student stu3 = new Student("wangba", 31);
    Student stu4 = new Student("zhaoliu", 17);

    List<Student> stu = new ArrayList<Student>();
    stu.add(stu1);
    stu.add(stu2);
    stu.add(stu3);
    stu.add(stu4);

    System.out.println("原始数据:");
    for (Student student : stu) {
        System.out.println(student);
    }

    System.out.println("进行排序......");
    StudentComparator studentComparator=new StudentComparator();
    Collections.sort(stu, studentComparator);
    for (Student student : stu) {
        System.out.println(student);
    }

    Student maxstu = Collections.max(stu,studentComparator);
    System.out.println(maxstu);
    }
}