关于return和finally

本来return和finally也不是个事。之前看虚拟机运行原理的时候就了解过。但是最近被人问起的时候，缺没有说清楚。所以整理一下记录下来。 
1.如果返回的是个对象，finally里的的代码，可以改变对象内部的状态。  

 package com.chinaso.phl;

 import java.util.ArrayList;
 import java.util.List;

 public class Test {

     public static void main(String[] args) throws Exception {
         Test t = new Test();
         System.out.println(t.check());
     }

     public List<String> check() throws Exception {
         List<String> name = new ArrayList<String>();
         name.add("phl");
         try {
             System.out.println("try");
             return name;
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             System.out.println("finally");
             name.add("piaohailin");
             for (int i = 0; i < 3; i++) {
                 System.out.println("time:" + (i + 1) * 300);
                 Thread.sleep(300);
             }
         }
         System.out.println("return");
         name.add("return");
         return name;
     }
 }

输出 
try 
finally 
time:300 
time:600 
time:900 
[phl, piaohailin] 

2.finally里面的赋值，不会影响返回结果  

 package com.chinaso.phl;

 import java.util.ArrayList;
 import java.util.List;

 public class Test {

     public static void main(String[] args) throws Exception {
         Test t = new Test();
         System.out.println(t.check());
     }

     public String check() throws Exception {
         String name = "phl";
         try {
             System.out.println("try");
             return name;
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             System.out.println("finally");
             name = "piaohailin";
             for (int i = 0; i < 3; i++) {
                 System.out.println("time:" + (i + 1) * 300);
                 Thread.sleep(300);
             }
         }
         System.out.println("return");
         name = "return";
         return name;
     }
 }

输出 
try 
finally 
time:300 
time:600 
time:900 
phl 

3.finally里带有return方法，则此return会覆盖try里面的return  
//warnning finally block does not complete normally 
一般不这么用，因为有警告信息，不够优雅 

 package com.chinaso.phl;

 import java.util.ArrayList;
 import java.util.List;

 public class Test {

     public static void main(String[] args) throws Exception {
         Test t = new Test();
         System.out.println(t.check2());
     }

     public String check2() throws Exception {
         String name = "phl";
         try {
             System.out.println("try");
             return name;
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             System.out.println("finally");
             name = "piaohailin";
             for (int i = 0; i < 3; i++) {
                 System.out.println("time:" + (i + 1) * 300);
                 Thread.sleep(300);
             }
             return name;
         }
     }
 }

输出 
try 
finally 
time:300 
time:600 
time:900 
piaohailin