How do I know if an array of Bytes is as large as 2MB

[Iratxe Monasterio]

Hi !!!!!!
How do I know if an array of Bytes is as large as 2MB, for example????
If anyone can help me ???
Thank you,

Iratxe

 

[Andrew Thompson]

Hi !!!!!!

Lo ((((((

How do I know if an array of Bytes is as large as 2MB, for example????

Well, we _could_

int numberOfBytes = array.length;

But no, wait.. that would _only_ help
if we knew how many bytes there were
in 2Mb.

OK. I'm stumped.

If anyone can help me ???

I dunno.. ;-)

 

[Darryl L. Pierce]

Hi !!!!!!
How do I know if an array of Bytes is as large as 2MB, for example????
If anyone can help me ???

byte[] array;

if(array.length == (2 * 1024 * 1024)) ...

 

[zebulon]

And is there a way to know the size taken in memory by any class instance ?

Hi !!!!!!
How do I know if an array of Bytes is as large as 2MB, for example????
If anyone can help me ???

byte[] array;

if(array.length == (2 * 1024 * 1024)) ...

 

[Darryl L. Pierce]

And is there a way to know the size taken in memory by any class instance
?

No.

 

[Christophe Vanfleteren]

No.

1.5 has sizeof.
Well sort of anyways:

http://java.sun.com/j2se/1.5.0/docs...entation.html#getObjectSize(java.lang.Object)

 

[Thomas Schodt]

1.5 has sizeof.
Well sort of anyways:

http://java.sun.com/j2se/1.5.0/docs...entation.html#getObjectSize(java.lang.Object)

Promise of "sizeof()" ...

Instrumentation is an interface, I had no luck locating a class that
implements it. On their ToDo list?

 

[Thomas Weidenfeller]

Promise of "sizeof()" ...

Instrumentation is an interface, I had no luck locating a class that
implements it. On their ToDo list?

I don't think so. From the API documentation:

<quote>
The only way to access an instance of the Instrumentation interface is
to use the -javaagent command line switch; this will cause an
Instrumentation instance to be passed to the premain method. Once an
agent acquires the Instrumentation instance, the agent may call methods
on the instance at any time.
</quote>

In other words, no sizeof().

/Thomas

 

[Darryl L. Pierce]

1.5 has sizeof.
Well sort of anyways:

http://java.sun.com/j2se/1.5.0/docs...entation.html#getObjectSize(java.lang.Object)

Cool. Can't wait until it's out in the wild (not beta) so I can start
mucking with it...

 

[Darryl L. Pierce]

http://java.sun.com/j2se/1.5.0/docs...entation.html#getObjectSize(java.lang.Object)

Promise of "sizeof()" ...

Instrumentation is an interface, I had no luck locating a class that
implements it. On their ToDo list?

No. You would get an instance of a class the implements the interface at
runtime. Why do you think you need a concrete class listed in the APIs?

 

[Joona I Palaste]

Thomas Schodt wrote:
http://java.sun.com/j2se/1.5.0/docs...entation.html#getObjectSize(java.lang.Object)

No. You would get an instance of a class the implements the interface at
runtime. Why do you think you need a concrete class listed in the APIs?

Because everyone knows there can't be instances of interfaces! Silly
Darryl!
Oh, wait, hang on...

--
/-- Joona Palaste ([email protected]) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"The day Microsoft makes something that doesn't suck is probably the day they
start making vacuum cleaners."
- Ernst Jan Plugge

 

[Thomas Schodt]

Thomas Schodt wrote:
http://java.sun.com/j2se/1.5.0/docs...entation.html#getObjectSize(java.lang.Object)

No. You would get an instance of a class the implements the interface at
runtime. Why do you think you need a concrete class listed in the APIs?

Would I not need a factory class or method? - Aah, it's me being a bit
dense.

To my defence, this is the first I hear of a premain() method.

 

[Darryl L. Pierce]

Because everyone knows there can't be instances of interfaces! Silly
Darryl!
Oh, wait, hang on...

Uh huh. Here, have another cuppa. Remember, *never* reply before your first
cuppa in the morning...

 

[Darryl L. Pierce]

Would I not need a factory class or method? - Aah, it's me being a bit
dense.

There will most likely be such a method provided to return to you a
singleton instance of a class that implements the interface. Since the
information is very platform specific, I'm sure that, like Toolkit, that's
the way it's going to go.

To my defence, this is the first I hear of a premain() method.

That's surely a part of the JVM itself and a reference to its C
implementation code.

 

[Thomas Schodt]

That's surely a part of the JVM itself and a reference to its C
implementation code.

When I Google for it, they all look like

public static void premain(
String options, java.lang.instrument.Instrumentation foo
) {
// body
}

so I expect it's similar to main().

 

[Darryl L. Pierce]

When I Google for it, they all look like

public static void premain(
String options, java.lang.instrument.Instrumentation foo
) {
// body
}

so I expect it's similar to main().

Hmmmm. I just assumed for some reason that it was a reference to
implementation. Apparently that was quite wrong of me to assume so. I've
not been tracking the new features with 1.5 but I'm guessing I'd better
check out the new specification and see what's up.

Does anybody know if there's a beta release for Linux as well?

 

[Christophe Vanfleteren]

Hmmmm. I just assumed for some reason that it was a reference to
implementation. Apparently that was quite wrong of me to assume so. I've
not been tracking the new features with 1.5 but I'm guessing I'd better
check out the new specification and see what's up.

Does anybody know if there's a beta release for Linux as well?

Yes there is:
http://java.sun.com/j2se/1.5.0/download.jsp

 

[Joona I Palaste]

Uh huh. Here, have another cuppa. Remember, *never* reply before your first
cuppa in the morning...

My message was intended to parody a common newbie problem.

 

[Darryl L. Pierce]

My message was intended to parody a common newbie problem.

Then give me back the coffee, seems *I* need it more.