答案（1）

 1 public class Singleton{
 2   /* 懒汉式 */
 3   private static Singleton instance = new Singleton();
 4   
 5   private Singleton(){}
 6   
 7   public static Singleton getInstance(){
 8     return instance;
 9   }
10 }
11 
12 public class Singleton{
13   /* 饿汉式 */
14   private static Singleton instance = null;
15   
16   private Singleton(){}
17   
18   public static Singleton getInstance(){
19     if(instance == null)
20         instance = new Singleton();
21     return instance;
22   }
23 }

 1 public void BubbleSort(int[] a, int n){
 2   boolean change = true;
 3   for(int i = 1; i < n && change; i++){
 4     change = false;
 5     for(int j = 0; j < n - i; j++){
 6       if(a[j] > a[j + 1]){
 7         int t = a[j];
 8         a[j] = a[j + 1];
 9         a[j + 1] = t;
10         change = true;
11       }
12     }
13   }
14 }