IBM Open Sources Their Own JVM/JDK As Eclipse OpenJ9 (eclipse.org)

IBM has open sourced a "high performance, scalable virtual machine" with "a great pedigree... [it's] at the core of many IBM enterprise software products." Slashdot reader dxb1230 writes: IBM has open sourced their JDK/JVM implementation named J9 as OpenJ9. The community now has an alternative implementation of Java which has been well tested on enterprise workloads and hardware. This unlike, OpenJDK, has all the bells and whistles like jit.

Comments

OpenJDK no JIT?

[Anonymous Coward]

Are you saying that OpenJDK doesn't have a JIT compiler? That seems untrue.

Why Java?

[Anonymous Coward]

Not intended as a troll, but a sincere question of a C-veteran of soon 20 years: why do people use Java?

To block the only apology I've heard so far - "portability": way back when (10 years or so?) Java-applications were a major PITA to install, as they needed Java version X.Y.Z; every last digit significant. It seems that these days applications have fixed this by shipping the entire Java run-time in the installation package. So the applications are not portable even between the language implementations.

Why not to use Java? The GUI UX seems to be stuck in the 1990's, and language has (at least to me) something offputting in its syntax.

So why do you choose java for your next project?

Re: Why Java?

[MightyMartian]

Largely my experience now. There are certainly a few incompatibility issues that creep up, after all Java is over 20 years old now, so that's quite a few iterations of both the language and the JVM. But when I consider the complexity of porting C code from, say, Linux to Windows, or in many cases from Linux to BSD or some other *nix flavor, the odd quirk I run up against when popping a JAR file on to a new platform, I'd say Java is as close as anything gets to true cross-platform portability. No one has put more effort into making obscuring the underlying architecture than the JVM teams, and I still get a thrill when I fire up a Java app I've written on Windows on my Linux test machine and it, well, just works. No recompiles, no wild makefiles and compiler redirectives.

C is an awesome language, and truly one of the great inventions of the computer age, but it is fundamentally a different tool than Java, with very different intentions. For me, Java means I'm not locked into any architecture, and not having to fight my way out of the box that the architecture represents. It's not for every task, but for the bulk of problems thrown at me, it does the job very well. Not perfectly, but very well.

It's not a JDK

[klingens]

The summary is wrong in several counts.
It's not a JDK but simply a JVM. A JDK would comprise at least a JVM, a java compiler and the needed class libraries. As the linked FAQ in the first entry says:
"Is Eclipse OpenJ9 a replacement for OpenJDK?
No. Eclipse OpenJ9 is a Java virtual machine (JVM), the engine that runs Java applications, whereas OpenJDK is a complete development kit that contains other components, like the Java class libraries, as well as a JVM. By default, OpenJDK builds with a JVM called Hotspot."

The "unlike OpenJDK also has all the bells and whistles like jit" is also wrong.
Hotspot almost 20 years ago replaced the JVM of that age which was a JIT compiling virtual machine, as was standard quite some time before. Hotspot however has JIT too but also does adaptive optimization on the fly which was the new cool thing back then. As wikipedia says:
" It features improved performance via methods such as just-in-time compilation and adaptive optimization." What it does and why it is called Hotspot is, it constantly checks what parts of the code are used the most often and it then optimizes those parts over time further if possible.
However it always uses JIT compilation like almost every other VM software does. Maybe IBM has some secret sauce JIT that Hotspot lacks, but the summary doesn't tell which or gives any other indication why IBM JIT is better than old Sun JIT