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Help crack the Java 1.6 Classfile Verifier
pdoubleya writes "As part of the development of Mustang (Java 1.6), Sun is developing a new, smaller and faster classfile verifier which they want your help in trying to break. As Sun VP Graham Hamilton puts it in his blog entry, "As part of Mustang we will be delivering a whole new classfile verifier implementation based on an entirely new verification approach. The classfile verifier is the very heart of the whole Java sandbox model, so replacing both the implementation and the basic verification model is a Really Big Deal.... The new verifier is faster and smaller than the classic verifier, but at the same time it doesn't have the ten years of reassuring shakedown history that we have with the classic verifier." You can read about the new verifier on Gilad Bracha's blog, and join the new Crack the Verifier initiative to if you can break it. Read all about the Crack the Verifier - Challenge."
No cold hard cash or equivalent for "cracking the verifier?"
I guess it could lead to more pay in some cases.
Before those who go on to dismiss Java for various reasons (no matter how ignorant they are), take a look at the presentation given by Google at this year's JavaZone conference on how Google is using Java internally at extreme scales. Among them are AdWords and GMail.
www.rexguo.com - Technologist + Designer
I'm not sure how the MS beta process works, but I get the impression that it's not just a straightforward download but you need to sign up or something (passport?).
I wonder what would happen if they junked the whole exclusive beta thing (which might get some of the more privacy-concerned, tech-savvy people on board? dunno - just a guess), and then actively encourage people to try and break the security? Surely that would produce better results than product x coming out, and then massive security problems follow for days, months and years afterwards.
I'm not pretending that this would cure the world of buggy ms software, but it can't hurt, can it? They should be doing it with vista right now.
Craig
If his name doesn't ring a bell, he's a Java guru who works for Sun and wrote the 2nd and 3rd editions of the Java Language Spec. A bunch of his papers are listed here.
It's a relief that JDK 1.6 won't include any language changes (as far as I know?). Updating various parsers and whatnot to work with all the JDK 1.5 language changes was a big job, although some of the new features certainly are quite handy.
The Army reading list
You mean like this; http://www.microsoft.com/athome/security/spyware/s oftware/default.mspx ?
Here you go:
https://mustang.dev.java.net/
It allows you to work faster and create more in a short while. It allows you to create abnormally slow programs that you can't even speed up with the willpower to do so, because of Windows internals. Those exact internals that Java won't touch with a stick.
// some function
// different, automatic polymorphism
// some function // some function too
// some other function! again automatic! // some function too, not polymorphic!
// function
// functiontoo
// override, kind of pointless...
// ... why new? that's reserved for memory allocation...
.NET (in C#) requires you to make everything you want so explicit that I'm inclined to say that you're wasting time doing that more than you're gaining time due to other factors.
Java doesn't look like win32 because it isn't even trying to. It's trying to look platform-independant and the same on all platforms, with the option to skin it to any GUI you want. dotNET IS windows. There's no wonder that it looks a lot more like windows.
I must strongly disagree on the OO implementation however, aside from it not supporting multiple inheritance, it's just good. Microsofts methodics are plain stupid, because for everything you want to do you have to specify it so explicitly my fingers still hurt last time I tried it.
Compare:
Java:
public class xyz {
int function() {
}
}
public class abc extends xyz {
int function() {
}
}
C++:
class xyz {
public: virtual int function() {
};
public: int functiontoo() {
};
};
class abc : xyz {
public: virtual int function() {
};
public: int functiontoo() {
}:
};
C#: (might contain errors, been a while)
public class xyz {
public virtual int function() {
}
public int functiontoo() {
}
}
public class abc : xyz {
public override int function() {
}
public new int functiontoo() {
}
}
My point is,
Plus, I just don't like their idea of a good library. Rape the C++ STL, why don't ya. Either support c++ (and the STL), or don't support it at all.
the onus isn't on the community, the onus is on the developers and their QA team. This is just an attempt to get a few more eyeballs on the verifier in case something falls through. There's nothing wrong with that.
Also it is an opportunity for someone to get recognition for breaking a new peice of software.
It is important to get extra scrutiny on newly designed peices of software, for it is the new designs that usually break in the least expected ways.
> C is portable, fast, very complex and since 35+ years the leading standard for professional OS and APP development.
.Net Framework is huge, there's no way that's simpler than the C standard library. Then you've got to think about reflection, inheritance, dozens of things that C just doesn't have.
I agree that C is portable and fast, however I don't it can be called very complex.
The smallest programming language manual I have ever owned (and I've owned quite a number), has to be "The C Programming Language", often hailed as the One True Reference to the language. How can it be that complex if the manual is less than half the size of most of my other manuals? I think languages (in general) have got more complex since then. The size of the
If what you mean is that C programs end up looking more complex, that's probably because C is used for systems programming. If you mean that you have to write more code to do it in C, then you may have a point, but I think C is actually one of the simpler languages. The closer to assembly you get, the simpler the language has to be.
Craig
Another nice thing about the new classfile specification is that it's going to make certain new kinds of optimization possible. The more you can prove about what's on the stack at any given point, the more you can inline.
Not only does inlining eliminate method call overhead, but it allows you to re-run the peephole optimizer, which can eliminate range checks, reduce redudant type checks, etc.
The ultimate performance promise of Java is that it can do optimization very, very late in the process. Native libraries are basically black boxes in C/C++, and it's very hard to do that sort of inlining because most of the type information has been lost. Java may, someday, with sufficient ingenuity, rival or even beat C++ in performance, and it already does in certain limited areas.
Of course C# has all of the same advantages, and even though it's more recent there are some areas where its performance beats Java. I'd love to see all the Microsoft reasearchers vs. all the Sun researchers coming up with increasingly brilliant ways to take advantage of the late binding to turn a performance hindrance into a benefit.
Why not do what it takes: Prove that it will work, and prove that it cannot be broken!
;)
Did you just walk out of an undergrad Computer Science class?
Popping in pre/postconditions and doing line-by-line proofs doesn't cut it for an application of this complexity. While that is an important part of a real process, it doesn't guarentee coverage. You still have to make assumptions about the environment, which is the gotcha. Testing and QA is all about the assumptions you make and the boundaries you set. With a complex application the number of factors grows so large, that you cannot have the resources to cover every possible test. You can grab the most common stuff, but really need to dump it to the community to get the real 'out of the box' thinking hitting it.
Help me take back Slashdot. When did 'News for Nerds' become 'FUD and Conspiracy Theories for Extremist Nutjobs'?
One thing's for sure: Improvements in software quality will be harder to come by if everybody's attitude continues to be "Bugs are inevitable. Formal proofs are beyond us. Let's keep doing it the old way."
Everybody's a libertarian 'till their neighbour's becomes a crack house.
Java 1.5 introduced the two things that make me willing to consider Java as a practical language for real work (as opposed to a "safe to let untrained programmers run rampant, too bad about the 10000k LoC required to do anything" language). Those two things are collections and generics.
... refreshing.
I was forced to use Java 1.2 some time ago, and found it a horrific experience with my background in dynamic languages. Since then, I've learned C++ and got used to the pluses and minuses of static languages (both in the sense of "compiled" and in the sense of "statically typed"). Java also largely ceased to suck, so having to work on it again and finding that sort code that would've been hundreds and hundreds of repetitive lines can now be expressed using a short set of comparitors and a collections-based sort was
After Java 1.5, I can understand why they'd want to let things settle down for a while. It seems to me that they finally got all the really important stuff into the language.
Look, I wish people who keep banging on about how Java is nearly as fast as C would get their heads out of their asses and realise that the biggest defect in Java is not raw execution speed but the "business processing" holiday that the system takes every "completely unpredictible once in a while". If I have a throughput capacity system, I can control the rate of throughput in a number of ways (eg selling less than my total capacity and then throttling at times of peak use) but when the system goes and does something like a garbage collection and the whole pipe goes "fnark" for a some seconds I am quite pissed since my users who want the service level in their SLA aren't getting it.
Predictability and execution control are why I use C (and to a lesser extent c++) not Java. That cannot change for languages that give me no control over the raw execution path.
"The first thing to do when you find yourself in a hole is stop digging."
I believe that there is a concurrent garbage collector in Sun's JVM that while not as effecient over-all but runs continously preventing pauses and bubbles associated with traditional garbage collectors.
I'm my Java in a Nutshell 4th Edition (p. 246) one of the java(the interpreter) arguments is:
As this book was written for Java 1.4 I'd bet it was fine-tuned and enhance for 1.5 and even more so for the upcoming 1.6. Might be worth trying out.Your CPU is not doing anything else, at least do something.
Pardon my ignorance, but isn't this a violation of the anti cracking clauses of the DCMA?
* java is nearly as fast as C++ according to all the benchmarks I've seen. Yes, really. The perception of java as being "slow" is simply the legacy of the old awt apps. Yes, the awt gui was (and is) slow. Server-side java applications are not. The "much better performance" is simply not there, particularly for typical enterprise apps.
* *All* the enterprise apps (which is the area where java is particularly successful) store stuff in a database and/or talk to remote apps. Newsflash: a database query or a remote procedure call is *orders of magnitude slower* than an in-process procedure call. Once you include DB/RPC into the equation, whatever little speed advantage C++ has is wiped out completely.
* This is CS 101: performance of a program is largely determined by the algorithm used. You can write a linear search in assembly, and it will be very fast for small lists. But for large lists, a binary search written in shell script will beat it.
* In an enterprise application scalability is much more important than raw speed. So what if I can write a C++ app that's 20% faster than an equivalent java app? Java has frameworks that make it easy to write an app that you can scale horizontally (i.e. by adding more boxes). Easy being the keyword.
* Developer's time is much more expensive than runtime. It is *much faster* to write an app in java than in C++. And for all but the smallest/simplest apps it is faster to write the app in java than in PHP/perl/whatever.
If it's a safety/security issue then again you could build the same thing in a native compiled language, sandbox and all.
Uhhhm, yes. Safety and security are *big* issues in enterprise apps. Show me *one* native language and platform that does it. You are saying it like one can just wave a magic wand and have it built in no time. "You could build the same thing" is not "it's already built".
I mean really, is it just because Java provides a lot of easy to use API's?
Yes. among all the other things I've mentioned.
These are just a few reasons why java is so popular in enterprise apps. Sure, I wouldn't write a game in java, but for enterprise apps, it's perfect. Why java and not PHP/perl/? Simply because java is better. It has all the advantages of compiled laguages (type safety, variable declaration checking, syntax checking, etc.) without some of the disadvantages (manual memory management). Think of java compiler as a sanity checker for your code. It will catch common mistakes like typos, missing return statements, invalid function parameters, etc. A scripting language will not complain about that, but force you to spend hours tracking down the bug. That's why java is faster to develop in than any scripting language for large apps.
___
If you think big enough, you'll never have to do it.
What I don't understand is exactly what advantage is Java providing on the server-side. Do you really need cross-platform bytecode at that level?
Actually, yes -- the cross-platform ability is extremely useful. Speaking personally: the two biggest projects I have worked on, both for one client, are deployed (production) on a IBM iSeries server (these used to be called AS/400s -- using the OS/400 operating system), and a Solaris server respectively. Both web apps are built on the same code base, and we developed and tested them on Windows 2000 workstations (XP, now, plus I am starting to do more and more development in RedHat Fedora).
Can you imagine if I needed my own iSeries at home to run a test server here? Those things aren't cheap. Also, because the client has more in-house iSeries experience, we're going to be moving the Solaris webapp to an iSeries as well at some point -- and guess what? The Java code doesn't need any changes whatsoever; it's only the database SQL that will need to be migrated (DB2 UDB to DB2400 SQL isn't consistent).
When I'm starting new projects, I can get people started on architecture and writing code in most cases *without* finalizing the eventual platform, and without getting access to the big hardware yet. You aren't locking yourself into anything from the beginning -- this is actually a pretty serious power to have. It also allows me to run side by side performance testing on servers to see the *real* differences in capabilities; this is HUGE because the folks selling the big iron suddenly are a commodity, not an unquestioned master in a domain with benefits we can't actually measure usefully.
Just my 2 cents -- I'm sure some people wouldn't actually care (e.g., "my webhost only runs RedHat, so that's all I need to care about"), but gotcha-free cross-platform code is a big deal.
Java Pros:
1. Zero memory fragmentation. The GC compacts the memory at runtime. This means indefinite uptimes. A server written in a refcounted script language might lack that.
2. Zero chance of a buffer overflow attack anywhere. Maybe if there is a bug in the VM, however, this might become possible.
3. All libraries in the standard distribution have been tested for almost a decade now.
4. Incredibly powerful multithreading and synchronization.
5. Rapid development of fast programs. Only someone well versed in Java can do that, but java is well worth it when you have the people. This can be done in other languages but at insane costs in security.
6. Performance costs for all of the above is within the 20% margin, which is great for a server app that does not do anything computationally expensive. Most of the work is offloaded to a fully optimized DB server anyway.
7. With the right framework, you can easily load and unload modules at runtime. Not easily done though.
Java Cons:
1. Incredibly slow startup time. It may take up to a minute for a large app to get fully loaded and JITed. This is a non-issue in a server environment, however.
2. Extreme memory usage. Up to 10 x the equivalent C++ app. However, the GC makes sure that memory usage remains almost constant under similar loads for months and years of uptime, because there is no memory fragmentation.
3. Due to 2, sometimes most of the memory gets swapped. This shouldn't happen in a server environment, but on a desktop running server apps (dev machines for instance) this is a great nuisance. It might take running a full GC manually to force your redmond-developed OS to re-load all the memory for the app. Again, a non-issue for servers.
4. The default Sun Java VM configuration makes Java run any program with a 64 megs of mem usage limit. This is ridiculous for a serious Java app. It takes passing a command-line param to fix that. People can get frustrated because of this.