Michael C. Alonzo ([EMAIL PROTECTED]) wrote To [EMAIL PROTECTED] on Mon, Feb 18, 2002 at 09:40:15PM +0800:
> my class is doing a prototype of a call center, ala > rescue 911... i suggested to them that we use Java but they > are having doubts if java can be use in mission-critical systems. > can someone cite a company or a corporation or some system that uses > java in their mission-critical systems? We use Java for map-based outage management in electric utility operations centers. see http://www.partnersoft.com With a few fairly simple additions to your software (e.g. reliable logging, including catching all STDERR and flushing your log files on VM shutdown) you can capture all errors other than out of memory and VM bugs. The various VMs have gotten very reliable; our system hub software (used in our design/job management system) is routinely up for weeks; it typically can stay up longer than the NT servers it usually runs on. If uptime is an issue, be sure to watch memory usage over long periods of time and system stress. You can still have memory leaks in Java - just not as conveniently as C :-). I consider the following to be the critical factors in critical systems: 1) no bugs in critical areas 2) hard separation between subsystems (including full try/catch (Exception oops) to catch and log all errors generated by subsystems and procedures such as saving files) 3) very reliable logging, including full stack trace 4) no chronic or longterm degenerative behavior, such as a memory leak 5) solid VM with no degenerative bugs or critical bugs of its own 6) good hardware/os substructure In general, (1) and (6) are a requirement for any implementation language, (2), (3) and (4) are IMHO easier to achieve in Java than in other languages. (5) is a Java-specific issue, but I've not had any problems with 1.3 VMs as far as uptime or critical bugs. IBM 1.1.x for windows had some sort of degenerative bug I never found - it would crash after a few days of uptime. Our software isn't generally critical in the sense of someone's life being on the line, or millions of dollars in cash; but it does help the utilities get power turned on more quickly to people who may be freezing/roasting to death in their homes etc., old people, etc. And it does increase safety as far as letting the ops know where their people are and aid analysis of which circuit is bad etc. Having worked on toxic waste cleanup analysis etc. I personally set a high standard on the word "mission critical" - I consider that sort of thing to be like atm software (lots of money), heart monitors (loss of life), or space-shuttle flight systems (both). Frankly, I wouldn't trust any language for these kinds of systems; you have to have a really seriously hard-core systematic approach to development that is totally different from the usual hackery. And I absolutely would not deploy such a system on a microsoft OS or standard PC hardware, since neither are reliable in any real sense of the word. But, for more common levels of "mission critical" I think Java is perfect. It insulates you from most common C bugs, it has better self-knowledge (in terms of monitoring the VM from within, stack traces, etc.) than most languages, and, very important for me, it adds an insulation and abstraction layer over the OS that prevents me from being caught (usually) by Windows bugs, since most of our clients run Windows. So tell them to stuff it; I've been writing full-time in Java for six years now and it's more than adequate for what you're describing. -- Paul Reavis [EMAIL PROTECTED] Design Lead Partner Software, Inc. http://www.partnersoft.com -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
