关于Java中的boolean类型所占存储空间

http://download.oracle.com/docs/cd/E17409_01/javase/tutorial/java/nutsandbolts/datatypes.html
boolean: The

boolean

data type has only two possible values:

true

and

false

. Use this data type for simple flags that track true/false conditions. This data type represents one bit of information, but its "size" isn't something that's precisely defined.

总是有人争论。确实一个bit可以表明，但是要看其工作原理，如果其工作是按字节处理数据，显然boolean被定义为一个bit会使得处理比较麻烦，因而不妥。
而我看到的中文论坛中顶多讨论到boolean是可以用1个bit表明，但不是被精确定义的到此为止。
但是作为一个要实现的内容，必须要有明确的定义，而这个定义是在JVM或是其他地方？
据搜，定义是在JVM
http://stackoverflow.com/questions/383551/what-is-the-size-of-a-boolean-variable-in-java
这帖有人给出了测量所占mem的程序例子
That suggests that booleans can basically be packed into a byte each by Sun's JVM.

http://www.velocityreviews.com/forums/t364574-size-of-boolean-type.html#6

It is up to the individual JVM implementation. It is possible that
different amounts of memory will be allocated in different situations.
However, the case that is both most interesting and most measurable is a
large boolean[] array.

I've previously measured it as one byte per element, rounded up to a
multiple of 8 and plus 8 bytes per array overhead. However, your mileage
may vary, and if you really need to know you should measure it on the
system you care about.

Patricia

http://www.daniweb.com/forums/thread33136.html#2
There is no need to know. A boolean is a boolean is a boolean. How it's defined internally is inconsequential to the person using the datatype.
It could even be different on different JVMs, so counting on a particular implementation is dangerous.
这位则说，内部如何定义不重要，刻意计算其占容反而会因为在不同JVM中定义不同而变得不安全。

http://forums.sun.com/thread.jspa?threadID=5434070 SIZE of Boolean

打开sun的JVM库的boolean，也看不懂也看不出哪里有写了占有多少内存。

原文地址：http://hi.baidu.com/redareyou/blog/item/649fb9119cc0dfcba7ef3f1b.html