1. 最简单的情形
public void main(){ String s = test(); System.out.println("s=[" + s + "]"); } public String test(){ String s = ""; try{ System.out.println("In try"); s += "try," ; }catch(Exception ex){ System.out.println("In catch"); }finally{ s += "finally,"; System.out.println("In finally"); } s+="other"; return s; }
输出的结果是：
In try In finally s=[try,finally,other]
2. 在try中加上return，那么结果是
public String test(){ String s = ""; try{ System.out.println("In try"); s += "try," ; return s; //加上return }catch(Exception ex){ System.out.println("In catch"); }finally{ s += "finally,"; System.out.println("In finally"); } s+="other"; return s; }
结果是
In try In finally s=[try,]
说明虽然会执行finally语句，但是return的结果已经准备好了。然后才执行finally，在执行finally之前，会将返回的结果存储到不同于s的变量中，finally执行成功之后，才会返回对应的结果。因此即使在finally中对结果进行修改，也不会修改返回的结果。
3. 如果在catch中return会怎么样呢？
public String test(){ String s = ""; try{ System.out.println("In try"); s += "try," ; throwException(); }catch(NullPointerException ex){ System.out.println("In catch"); s += "catch,"; return s; }finally{ s += "finally,"; System.out.println("In finally"); } s+="other"; return s; } public void throwException() throws NullPointerException{ throw new NullPointerException(); }
执行结果是：
In try In catch In finally s=[try,catch,]
可见道理是一样的，也就是不管在try还是在catch中的语句中return的结果，即使在finally中进行修改，都不会改变结果。
4. return 语句先执行，还是finally先执行呢？
public String test(){ String s = ""; try{ System.out.println("In try"); s += "try," ; throwException(); }catch(NullPointerException ex){ System.out.println("In catch"); s += "catch,"; return s += testReturn(); }finally{ s += "finally,"; System.out.println("In finally"); } s+="other"; return s; } public String testReturn(){ System.out.println("In Return"); return "return,"; } public void throwException() throws NullPointerException{ throw new NullPointerException(); }
结果是：
In try In catch In Return In finally s=[try,catch,return,]
也就是，return还是要比finally先执行，但是这时函数还没急着返回，只有把finally执行完才会返回。
总结的结果是：
1. 不管是否有异常，finally都会执行
2. 即使try或catch中有return语句，finally仍然会执行
3. finally中语句是在return语句之前执行的，即return语句执行就决定了返回的结果
4. return语句执行完如果还有finally块，还会执行finally块，但是无法修改return语句返回的结果
参考资料：
http://www.cnblogs.com/ybwang/archive/2010/10/10/1847269.html