All about Java

[Howell]

So I know Java is a programming language designed and maintained by Sun to be very portable.

I can see that there are some options in IEs options for "Java VM" but I also know that I had to download and install something from Sun so that Arachnophilia and some Novell tools would work.

Can I get a general overview of the technology and an explaination of when the IE portion can/should be used vs. a situation necessitating
a trip to sun.com?

Also, there appear to be several JREs available I assume like the one I downloaded from Sun. Why and how do you pick one?

 

[blakerwry]

The JRE acts as sort of an emulator, or atleast a middleman. It allows java byte-code (i believe that's the correct term) to run on your system or any other.

To understand the place of the Jave run-time environment (JRE) you have to have a brief introduction to the concept of JAVA. Since JAVA was designed to be portable, programs need a way to easily run on any system without having to modify the code used in making a program. The way Sun implemented this is to have the programmer code their program and then pseudo compile it into what is known as java byte-code. That code is fully portable and can be ran on any system with a JRE installed. The JRE's job is to interpret that byte-code correctly and then run it on the host system. Each platform (win16, win32, winNT, Mac, Linux, Unix, etc) has a very differently programmed JRE. The programming is different, but the purpose is the same. Interpret the program and run it using the tools available on that platform.

Idealy you should only need a JRE of the same or later version of JAVA as what the program you are running was compiled with. However, certain versions of the JRE might have bugs on some platforms. Additionally, different companies have decided to make their own JREs. I trust SUN's JRE over the others, but I know Merc has recomended IBM's. Microsoft's JRE is probably pretty bad comparatively, but probably integrates best with windows.

If I could only have 1 JRE installed, i would use SUN's. But fortunately, I dont think there is a problem having multiple JRE's installed. Bottom line, use what works... Some programs may have been written in such a way as to only work with (or work best with) a certain platform and run-time environment. The readme/help file of the program probably has recomendations on what version/brand of JRE to use for best results.

 

[Mercutio]

Microsoft's VM is serviceable but old. It doesn't match up to date specs, and some new apps made for actual cross platform compatibility won't work with it (most java apps are made to work with the Microsoft's VM).
Sun's is completely up to date. It's not well optimized for Windows, probably for political reasons.

IBM's Webshere JVM is top of the heap right now. IBM's done more productive work with Java than Sun has (and with good reason, given its product lineup), and their product is up to date and well-optimized.

 

[Howell]

Bugs aside, are the JRE implementations from different vendors supposed to be directly interchangable?

Can you compiled java programs to be stand-alone and need no JRE? This would of course alter the final programs portability.

 

[Mercutio]

Not quite. Different VMs work with different specifications of the language, and some leverage proprietary extensions (coughMScough). In theory, given the same language spec, the VMs should work the same, albeit more slowly or quickly depending on implementation. Microsoft lost a lawsuit to Sun over this - their JRE behaved differently from Sun's spec, and MS got a spanking because of it.

There's no "One True VM", except that you should probably use the one used by the people who developed your app.

AFAIK, there's no way to make a true java binary. The semicompiled byte code is as close as things get.

 

[Howell]

IBM's Webshere JVM is top of the heap right now. IBM's done more productive work with Java than Sun has (and with good reason, given its product lineup), and their product is up to date and well-optimized.

IBMs website is very confusing compared to Sun's. I went looking for something smaller than that which you linked to. While looking around I think I saw where IBM's Vm is 1.3.1 based while Sun's is now 1.4.2 based. Is that number the language spec?

I also found this site that might be helpful for people with my original questions. I've not read through it yet but it appears to be basic progressing to thorough.

 

[Howell]

I also found this site that might be helpful for people with my original questions.

Not to say that you guys weren't helpful.

 

[mubs]

Being the world's largest computer corp., IBM still doesn't know how to sell. Ever try to buy a PC or a notebook from them? The signal-to-noise ratio is incredibly bad. They also expect you to spend thousands with little or no information. Contrast that to Dell; while Dell is no paragon of virtue, they're better than anybody else when it comes to product detail. HP's trying to catch up; they've improved a lot, but still have a ways to go. IBM's the absolute pits. ANd this is the company that had that multi-year campaign that said they were the experts and would e-enable your business.

 

[Mercutio]

Unlike Dell, IBM has an army of VARs and consultants, including its various service arms, to explain and promote its products. The challenge when dealing with IBM is getting to the actual experts, instead of the random know-nothings that float around most service firms. Dealing with IBM can be very, very bad, but it can also be just this side of amazing.

IBM stuff DOES cost more. In my experience it's also a lot better (perhaps over-engineered is a better term) than the crap the other big guys in the PC world make.

Also, I'm pretty sure Dell and HP are both bigger, at least in terms of market cap, than IBM.

 

[CityK]

IBM's Webshere JVM is top of the heap right now. IBM's done more productive work with Java than Sun has (and with good reason, given its product lineup), and their product is up to date and well-optimized.

IBMs website is very confusing compared to Sun's. I went looking for something smaller than that which you linked to. While looking around I think I saw where IBM's Vm is 1.3.1 based while Sun's is now 1.4.2 based. Is that number the language spec?

Is there any way of getting IBM's J2SE without d/l'ing and installing all that websphere stuff?

Would IBM's plugin work with Firefox?

 

[Mercutio]

There's no way to get IBM's unencumbered VM without Websphere. They more-or-less give away developer tools but the client software isn't not free.

 

[e_dawg]

Unlike Dell, IBM has an army of VARs and consultants, including its various service arms, to explain and promote its products. The challenge when dealing with IBM is getting to the actual experts, instead of the random know-nothings that float around most service firms.

Good point.

IBM stuff DOES cost more. In my experience it's also a lot better (perhaps over-engineered is a better term) than the crap the other big guys in the PC world make.

Which products, specifically? Their notebooks do seem quite well engineered, although I can't say that I've ever had a pleasant experience using them. 2 Thinkpads were like porcelain dolls, their TFT displays, motherboards, floppy drive, and CD-ROM failing within a year or two. Another 2 had incessant stability and bugginess problems, although the software and drivers obviously need to share much of the blame with the hardware.

 

[Mercutio]

On the other hand, 260lbs. of me once put my full-weight foot on a T20 LCD without breaking it.

And then there's my oldest Thinkpad, a 560. 233MHz and it'll boot off a theorectically non-bootable Soyo Cig@r USB thumb drive.

Other joys I've encountered: Finding a P5-100 desktop with BIOS flashes new enough and good enough to let it use a WD4000BB; Discovering that almost everything IBM has sold in the last 10 years (except that stupid mwave modem/soundcard) has been relatively standard and replaceable; realizing that IBM's desktops are pretty much the heaviest on the market*; calling IBM.net in 1996(!) and being routed directly to a Linux support guy when my first experiments with NAT weren't going so well.

The thing about they heavy desktop: I realize that it's a very shallow way to judge electronics of any kind, but there's some truth to the notion that a heavier device is generally better than something in the same class, that's lighter. If nothing else, the power supplies I've seen in recent-vintage IBM desktops have been heavyweights compared to Dell and Compaq's anemic units.

At any rate, out of all the big vendors, IBM has given me the best experience. Some of their laptops DO suck, but their average is much, much higher. I'd stake a T-series notebook against anything Compaq ever made.

IBM printers, however, are proof that we're trapped in a cold, uncaring universe.

 

[Fushigi]

The thing about they heavy desktop: I realize that it's a very shallow way to judge electronics of any kind, but there's some truth to the notion that a heavier device is generally better than something in the same class, that's lighter.

Our AS/400 frames weigh from 600 - 900 pounds each. Lots of steel. There are enough sheet metal screws that you can wear out a cordless screwdriver opening them up.

 

[e_dawg]

... realizing that IBM's desktops are pretty much the heaviest on the market ...

IBM printers, however, are proof that we're trapped in a cold, uncaring universe.

Compaq DeskPro EN desktops from the mid-late 90's are heavyweights too.

Weren't IBM printers (lasers) made by Lexmark for quite some time?

 

[sechs]

Lexmark was IBM's printer division. (Please recall the the "BM" stands for "business machines.") Unlike their typewritters, IBM printers seemed to be not very good, although reliable.

The real problem with IBM computers is that they don't physically break down in an appropriate manner when it's time to upgrade. They just keep chugging along.

 

[P5-133XL]

Old IBM keyboards compete well with any other keyboard including the old Northgates omni-key ultra's: I like my keyboards to have some weight attached along with the appropiate clicky feel. New keyboards - Yuk, Yuk, Yuk.

Generally I very much like IBM equipment. Very little proprietary stuff, overdesigned, solidly built, and similarly priced to their competators (i.e. compaq)