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Comment by wmf | Hacker News Reader

It's important to understand that Android doesn't use Oracle's open-source OpenJDK. An argument could be made that Oracle licenses the necessary patents only for OpenJDK and not for alternate implementations such as Dalvik. An argument could be made that Oracle licenses patents only for JVMs that are TCK-compliant, which Dalvik isn't. An argument could be made that Oracle licenses patents for GPLed JVMs but not for ASL-licensed JVMs (because ASL is "too free" perhaps?)

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Thank you for this explanation. Until reading it this way my understanding of the whole affair was somewhat wrong.

Given that Oracle doesn't seem shy about going after a giant like Google makes me wonder what other software Sun owned the rights to that might be even remotely popular. If I were a company using a lot of old Sun IP in even moderately unique ways, I'd be a little concerned right now.

MySQL? BerkeleyDB?

Well, Sun own MySQL. But the drop-in replacement MySQL engine makers (infobright, percona, etc) might be a little worried.

The comment you're replying to pointed out that Oracle owns MySQL (acquired with Sun) and BerkeleyDB (acquired with SleepyCat).

I had forgotten they also owned BerkeleyDB (obviously I know that Oracle own Sun, is that why I'm getting downmodded?).

But my point still stands: makers of replacement engines for MySQL could be in violation of MySQL-related patents, which Oracle could then sue over.

They could, but they haven't, and probably won't. Oracle had a big database-related portfolio long before they acquired Sun/MySQL, which had relatively few. They even bought Innobase, makers of the InnoDB engine a few years ago.

Other database vendors (Percona et al., not IBM) don't have assets for Oracle to take, don't directly threaten their core business, and going after them would get Oracle in trouble with regulators.

Better to land a tuna than chase sardines around.

Thanks, it naively hadn't occurred to me that Android would be using a non-Sun JVM, and given what you've said it seems that would be a viable route for an IP lawsuit (though it still seems in pretty bad faith).

Dalvik would be better if Google had just licensed Oracle's Sun JVM or used the open source version. As an occasional Android developer I am constantly banging against the limitations and performance of Dalvik.

It doesn't do memory management nearly as well as the JVM, and it handles dynamic dispatch and one-off closure hacks (local classes) slowly. It won't easily accept generated bytecodes. It has mysterious performance headaches (mostly memory management related I think).

I'd prefer that Oracle go to heck with these bogus patents for the health of the industry but Google should have just cooperated from the start.

On the flip side, how do you know you wouldn't run up against those limitations on a phone that used OpenJDK? I don't do much mobile dev, but I've had friends that did JavaME development, and they didn't seem to like it any more than Android. Dalvik was designed specifically because Sun's JVM performed poorly on memory-constrained devices.

In other words, your issues may be caused by mobile development, not by Android development.

Given that Eric Schmidt is the former head of Java at Sun, it seems unlikely they'd have written their own JVM if they didn't have a good reason to do so. Also, JavaME is awful.

The Sun JVM is a lot of things and got a lot better and a lot faster over time, but it is an astounding memory hog. Only thing I've ever seen that will (seriously) reserve 64 bits for a Boolean field on a 64-bit VM.

Dalvik is a register based VM, as opposed the the stack based JVM.

Also Sun removed the classpath exception when they put JavaME under the GPL. That means if you used the GPL'ed version of Java on a mobile device then it becomes viral - including to any application code. (That's why most GPL'ed Java programs use the classpath exception).

From Sun's point of view, this was a good idea because it allowed them to protect JavaME licence revenue. Google saw JavaME as outdated, though, so instead of licencing it they took the Apache licensed Harmony project (ie, a clean room, Apache licensed version of the Java class libraries) and build Android around it.

You haven't worked with Java ME then ;)

Dalvik limitations are very justified, and even if phones improve over time, Dalvik also evolves.

Also when going head to head with Apple and Microsoft on such a far-reaching platform, having full control over your platform is valuable.

another technical reason for going with a new VM: every process (e.g every app) runs its own VM for security purposes. dalvik claims to have a much lower memory footprint.

http://www.youtube.com/watch?v=G-36noTCaiA

There wasn't any cooperation available, unless Google wanted to pay megabucks for Java ME, and force their developer chain to do the same: Java ME was never open sourced.

Essentially, Sun said "We will give away Java, Open Source, as we planned to do. Oh, not mobile, because Nokia uses it and it makes us lots of money. Of course, we all understand reimplementing Java ME would be far too much work for any one company to do. Feel free to license."

Google said "Eh, we'll just write our own JVM that runs on phones, thanks. That's how we roll over here."

Now there are lawsuits, because Sun tried hard to make sure you had to pay if you wanted Java on mobile devices.

I know "great comment" comments are silly, especially in a vote-based comment system, but seriously, great comment. Very instructive.

What if I take the open source OracleJVM and change every line, so that it become Dalvik? Wouldn't it still be derived from OracleJVM and hence covered? The approach would only be possible because Dalvik is open source, too, of course.

Your implementing a different instruction set.

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