List<String> stringList = new ArrayList<String>(); 
stringList.add("nice"); 
stringList.add("delicious"); 
stringList.add("able"); 
stringList.add("moon"); 
stringList.add("try"); 
stringList.add("friend"); 
 
Collections.sort(stringList); 
 
for (String str : stringList) { 
  System.out.println(str); 
} 

@SuppressWarnings("unchecked") 
public static <T extends Comparable<? super T>> void sort(List<T> list) { 
  Object[] array = list.toArray(); 
  Arrays.sort(array); 
  int i = 0; 
  ListIterator<T> it = list.listIterator(); 
  while (it.hasNext()) { 
    it.next(); 
    it.set((T) array[i++]); 
  } 
} 

public static void sort(Object[] array) { 
  // BEGIN android-changed 
  ComparableTimSort.sort(array); 
  // END android-changed 
} 

Comparable<Object> pivot = (Comparable) a[start]; 
int left = lo; 
int right = start; 
assert left <= right; 
 
while (left < right) { 
  int mid = (left + right) >>> 1; 
  if (pivot.compareTo(a[mid]) < 0) 
    right = mid; 
  else 
    left = mid + 1; 
} 

public final class Integer extends Number implements Comparable<Integer> 

public final class String implements java.io.Serializable, Comparable<String>, CharSequence

public int compareTo(T o); 

public class MainTest {  
 
  public static void main(String[] args) {  
    List<User> userList = new ArrayList<User>();  
    userList.add(new User("Lucy", 19));  
    userList.add(new User("Jack", 19));  
    userList.add(new User("Jim", 19));  
    userList.add(new User("James", 19));  
    userList.add(new User("Herry", 19));  
    userList.add(new User("Luccy", 19));  
    userList.add(new User("James", 18));  
    userList.add(new User("Herry", 20));  
 
    Collections.sort(userList);  
 
    for (User user : userList) {  
      System.out.println(user.getName() + "\t\t" + user.getAge());  
    }  
  }  
 
  private static class User implements Comparable<User> {  
 
    private String name;  
    private int  age;  
 
    public User(String name, int age){  
      this.name = name;  
      this.age = age;  
    }  
 
    @Override 
    public int compareTo(User another) {  
      int compareName = this.name.compareTo(another.getName());  
      if (compareName == 0) {  
        return (this.age == another.getAge() ? 0 : (this.age > another.getAge() ? 1 : -1));  
      }  
      return compareName;  
    }  
 
    public String getName() {  
      return name;  
    }  
 
    public int getAge() {  
      return age;  
    }  
  }  
} 

Herry    19  
Herry    20  
Jack    19  
James    18  
James    19  
Jim   19  
Luccy    19  
Lucy    19 

private static class User implements Comparable<User>

public class MainTest {  
 
  public static void main(String[] args) {  
    List<User> userList = new ArrayList<User>();  
    userList.add(new User("Lucy", 19));  
    userList.add(new User("Jack", 19));  
    userList.add(new User("Jim", 19));  
    userList.add(new User("James", 19));  
    userList.add(new User("Herry", 19));  
    userList.add(new User("Luccy", 19));  
    userList.add(new User("James", 18));  
    userList.add(new User("Herry", 20));  
 
    Collections.sort(userList, new Comparator<User>() {  
 
      public int compare(User user1, User user2) {  
        int compareName = user1.getName().compareTo(user2.getName());  
        if (compareName == 0) {  
          return (user1.getAge() == user2.getAge() ? 0 : (user1.getAge() > user2.getAge() ? 1 : -1));  
        }  
        return compareName;  
      }  
    });  
 
    for (User user : userList) {  
      System.out.println(user.getName() + "\t\t" + user.getAge());  
    }  
  }  
 
  private static class User {  
 
    private String name;  
    private int  age;  
 
    public User(String name, int age){  
      this.name = name;  
      this.age = age;  
    }  
 
    public String getName() {  
      return name;  
    }  
 
    public int getAge() {  
      return age;  
    }  
  }  
} 

Collections.sort(userList, new Comparator<User>()) 

public static <T> void sort(List<T> list, Comparator<? super T> c)

public static <T> void sort(T[] a, Comparator<? super T> c)

private static void mergeSort(Object[] src, Object[] dest, int low, int high, int off, Comparator c) 

if (length < INSERTIONSORT_THRESHOLD) {  
  for (int i=low; i<high; i++)  
  for (int j=i; j>low && c.compare(dest[j-1], dest[j])>0; j--)  
    swap(dest, j, j-1);  
  return;  
}