I hope this is the codename for the upcoming Chinese JME 5 KVM.
On Feb 24, 7:27 pm, Joshua Marinacci <jos...@gmail.com> wrote:
> Ancient Kung-fu Magic (tm)
>
> On Feb 24, 2009, at 9:19 AM, mbien wrote:
>
>
>
> > Hello,
>
> > I am curious. JavaFX bytecode makes heavy use of annotations, many
> > javafx RT classes also use enums and generics. How should this run on
> > a 1.4 J2ME KVM?
>
> > regards,
>
> > michael
>
> > On Feb 24, 5:41 am, Derek Munneke <derek.munn...@gmail.com> wrote:
> >> Just to make sure that everyone is on the same page, the JavaME
> >> platformdoes not runon the theJava Virtual Machine, unlike JavaSE,
> >> JavaEE (or JRuby, Jython, Scala, etc..)
> >> JavaME applications run on a "K Virtual Machine" ('K' for KB
> >> (40-80KB in size!), or cause it comes after the letter 'J'); this
> >> runtime environment does not confirm to the JVM specification.
> >> Areas where a KVM differ from the JVM
> >> <http://java.sun.com/products/cldc/wp/#spec
> >> >Large data types: long, float, and double -- many configurations
> >> do not need the extended range and precision of the larger data
> >> types.Multi-dimension arrays -- many configurations do not need to
> >> support arrays of more that one dimension.Class file verification
> >> -- some specified configurations may not need to support on-device
> >> verification of class files. Instead technology is planned to be
> >> developed to enable class files to be efficiently verified "off-
> >> line" and delivered to the device.Handling of Error classes -- when
> >> the Java virtual machine encounters a serious internal problem, it
> >> throws an instance of a subclass of java.lang.Error. However,
> >> because there is often no reasonable form of programmatic recovery
> >> from these errors, a configuration may specify the KVM to halt with
> >> a configuration-defined error indication. Or the configuration may
> >> allow device vendors to define device-specific behavior and
> >> recovery actions when it encounters such conditions.Threads and
> >> event handling -- some configurations may require a different
> >> application execution model from the standard Java technology-based
> >> model using the Thread class and standard event handling.Java
> >> Native Interface (JNI) -- many configurations might not need the
> >> flexibility of the JNI for the way in which native methods are
> >> linked and invoked. A configuration may use a defined alternative,
> >> simpler mechanism to invoke native methods.Class loaders -- many
> >> configurations might not need the full flexibility of Java class
> >> loaders. A configuration must specify the mechanisms by which
> >> classes are located and loaded into the KVM.Finalization -- many
> >> configurations do not need to support object finalization.Maximum
> >> size limitations -- many configurations do not need to support the
> >> full range of sizes of internal virtual machine data structures. A
> >> configuration may specify a "maximum supported" range for some or
> >> all of the following values:The number of classes in a packageThe
> >> number of interfaces implemented by a classThe number of fields in
> >> a classThe number of methods in a classThe number of elements in an
> >> arrayThe number of bytes of code per methodThe length of a string
> >> in a CONSTANT_UTF8 constant pool entryThe maximum amount of stack
> >> that a method may useThe maximum number of locals that a method may
> >> useStart-up -- each configuration must specify how the KVM locates
> >> the initial class and method to execute and the expected attributes
> >> of that class and method.
> >> Another thing of note, on a phone you can't just install your KVM
> >> of chose since the platforms are mostly closed; so you are stuck
> >> with what ever the device vendor provides, expect on "smart phones"
> >> that provide an Open OS that allow binaries to be ported and loaded
> >> [1] ; does this mean the iPhone is not a smart phone?
> >> This also means there are at least a dozen main KVM's in use, and
> >> many more, so unlike in the desktop world where you can specify a
> >> JVM your product will work on, in the mobile world you have to
> >> program for all of the KVM quirks (as well as devices differences
> >> like screen size, graphics offsets, input methods, and hardware
> >> services).
> >> And as Jess mentioned, this also means that when/if a new KVM
> >> version is released, the users cannot just install the update; so
> >> we are stuck with what we have got if we want to reach any kind of
> >> majority of the 4 billion mobile phone subscribers.
> >> /derek
> >> [1] my definition of a smart phone.
> >> Alex Buckley wrote:On Feb 17, 7:47 am, Brian
> >> Frank<briansfr...@gmail.com>wrote:The Java modularity work has
> >> changed directions a couple times, so I am not completely sure what
> >> the current design is. But I think it can go a long way to the
> >> solve the J2ME problem if the following holds true: 1. The "kernel"
> >> is similar in size and scope to what J2ME is today 2. The
> >> modularity is granular enough that big subsystems like AWT, Swing,
> >> and CORBA don't get sucked in because you wanted something from NIO
> >> (just a silly example, but there are some weird package inter-
> >> dependencies) 3. A suitable licensing model is provided such that
> >> you don't have to ship a device with every J2SE module.You are
> >> basically describing the JRE/JDK modularization story that Mark
> >> told at Devoxx:http://tinyurl.com/cm5qmy:-) The Jigsaw module
> >> system has a bunch of features to support profiles; subsetting and
> >> refactoring of the SE APIs; and (perhaps) feature-based provider
> >> selection ("give me a module with MP3 and Ogg support"). Alex
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