Porting CLDC Hotspot VM

Hello,
I want to port CLDC Hostspot VM to an OS running on ARM9 processor.
Where can I download CLDC Hotspot VM source code ?
Thanks In Advance,
Regards
Surendra

If you don't get a definitive answer here, you might try asking on the hotspot-dev (at) openjdk.java.net mailing list. That's where all the HotSpot developers hang out. I know there are people there working on an ARM9 port, though I don't know if it's for the full Standard Edition or CLDC.

Similar Messages

  • Regarding CLDC Hotspot

    Hi,
    i am Mukesh From India Bangalore. can any one help me in setting the cldc hotspot implemation ? i mean what are all things required to setup the development enviorment,i have gone through the white papers but it is not clear how to set up.
    secondly i am working on J2ME Application using wtk2.3 beta version, i would like to enable & disable JIT(Just in time) Compiler.
    and last query is: How can i do make my methods as inline ? (Wait before you answer this question) i have already tried my hands with static, final, private, making local variables, but no use @ all.
    -Waiting for you quick response.
    -Mukesh
    Bangalore
    India.

    {color:#000080}Your question is not at all clear, but if you're looking for an IDE for j2me you could try NetBeans, a free product from Sun, with the Mobility pack and WTK 2.5.1 (or latest).{color}
    i have already tried my hands with static, final, private, making local variables{color:#000080}Doesn't make sense to try stuff without understanding. Programming is not a lottery. I suggest you go through some Java tutorials, such as those available at
    {color}{color:#0000ff}http://java.sun.com/docs/books/tutorial/index.html{color}{color:000080}
    To ask better questions which in turn get you better answers, read
    {color}{color:#0000ff}http://catb.org/~esr/faqs/smart-questions.html{color}{color:000080}
    db{color}

  • InPlace execution in CLDC hotspot implementation

    I am working on Inplace execution feature given by SUN in CLDC Hot spot Implementaion. I want to know how much performance can be increased by using inplace execution for the midlet to be run on the device. I have converted the midlet jar file into application image (bun) but not able to know whether I have got any significant improvement or not.
    Can anybody tell me that how can inplace execution improve the performance and it will affect which part? Is there any way to know how much performance has been increased like some benchmark midlet for InPlace Execution feature.
    Please provide some help.

    This type of emulation is called HLE, there are some drawbacks to this approch. The one that i think prevented implementors of an VM to go this road is that it's verry hard to compile all bytecode to native code and be sure there are no security problems. Also the general protection failts will come to your java code! Of cause this can be prevented by putting in a lot of overhead code for every bytecode instruction, but then it's not fast anymore! ;o)

  • Porting CLDC code to CDC

    Hello,
    i have been implementing an application using J2M2 MIDP2.0 CLDC1.1.
    is it possible to run the midlet in a PDA(CDC profile) ?
    Is it possible to somehow port to it to CDC profile with minor changes? or do i have to code everything from scratch suing CDC libraries?
    thanks a lot
    sebastien

    The GUI will need redoing. Any RecordStore usage will need reworking to use java.io. Anything else from javax.microedition will need a substitute.

  • Porting HotSpot?

    I am looking for information on porting HotSpot to the ARM/Linux platform. Currently, the Blackdown project has a VM for the ARM platform but no JIT whatsoever. Performance is a critial part of the project I am working on, and the interpreted mode execution is just too slow, to the point that simple UI behaviors are quite sluggish.
    This is an embedded system with a 640x480 color LCD display and a 300MHz ARM processor. We should be able to get adequate performance out of it, but without a JIT, we are probably going to have to scrap everything and switch to C++. Hardware modifications such as a Java coprocessor or accelerator are out of the question this late in the development process.
    So we are looking for help, and may be able do, or support others in doing, a port of HotSpot to ARM/Linux. Two questions:
    1. Is this feasible? I assume HotSpot can plug into the Blackdown JDK, because I know the Blackdown JDK 1.3.1 for i386/Linux uses HotSpot by default now.
    2. How much work would this take? Or are there other JITs out there that would be easier to port?
    I read on Sun's HotSpot white paper that HotSpot is basically table-driven, and if it is as simple as entering data on a new processor architecture, it seems like a relatively easy task.
    Thanks for any ideas, I am really searching for anything that can help us out.
    Cheers,
    Colin

    Hi,
    Since yesterday iam searching for this kind of task. But i did not found any answer.But after reading extensively about embedded systems(ARM etc etc) with java, i found java is too young to embedded systems.I heard, HP has made another JVM for embedded systems, which is superior than SUN JVM. But i dont know how much that will help you.
    But I sincerly suggest go with C/C++ which is proven for embedded systems.Please dont rely on SUN until they come up with few sucess stories of their JVM on ARM.
    If you found any thing please let me share it.
    Regards,
    uppala

  • Porting MIDP2.0 to arm xscale ARCH

    Hi,
    I have ported cldc 1.1 to arm xscale ARCH. Now i am trying to port MIDP2.0 to the same ARCH. I am getting struck while linking "midp"... Below is the error message from make....
    no need to recompile .java files
    Linking ... bin/midp
    /opt/Olai/arm-xscale-linux-gnueabi/gcc-4.1.2-glibc-2.5-kernel-2.6.18/lib/gcc/arm-xscale-linux-gnueabi/4.1.2/../../../../arm-xscale-linux-gnueabi/bin/ld: ssl_obj/bnlib.o: Relocations in generic ELF (EM: 3)
    /opt/Olai/arm-xscale-linux-gnueabi/gcc-4.1.2-glibc-2.5-kernel-2.6.18/lib/gcc/arm-xscale-linux-gnueabi/4.1.2/../../../../arm-xscale-linux-gnueabi/bin/ld: ssl_obj/bnlib.o: Relocations in generic ELF (EM: 3)
    ssl_obj/bnlib.o: could not read symbols: File in wrong format
    collect2: ld returned 1 exit status
    imake: *** [bin/midp] Error 1
    It seems object files in ssl_obj directory is for intel i386... Does anyone know how to solve this problem???
    regards
    hrs

    hi,
    i am also try to port cldc1.1 and midp2.0 to arm + linux this days. i have successfully cross-compile the kvm1.1. but it fails to run a java program with floating-point operations. it quits without any prompt as soon as the java program goes to a floating-point operation.
    it would be very nice of you to share some of your successful experience with me. looking forward to your e-mail. thank you very much.

  • Web service and ejp enterprise in JBoss

    Is Java a compiled language?
    Actually, Java is a compiled/interpreted language. See the links below. This is the best classification for the Java language, in my opinion. Read [_this thread_|http://forums.sun.com/thread.jspa?threadID=5320643&start=0&tstart=0] and give your opinion, too! You are very welcome in this interesting discussion. The more I participate in this forum, the more I learn. The more you participate the more you learn, too! Thank you very much for this forum, Sun!
    [_CLDC HotSpot Implementation Architecture Guide Chapter 10_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/VFP.html]
    +The 1.1.3 release of CLDC HotSpot Implementation included limited VFP support. This feature was supported only when running in interpreted mode. In this release, full vector floating point support is provided when the virtual machine is running in compiled mode.+
    [_Java Virtual Machines_|http://java.sun.com/j2se/1.4.2/docs/guide/vm/index.html]
    +Adaptive compiler - Applications are launched using a standard interpreter, but the code is then analyzed as it runs to detect performance bottlenecks, or "hot spots". The Java HotSpot VMs compile those performance-critical portions of the code for a boost in performance, while avoiding unnecessary compilation of seldom-used code (most of the program). The Java HotSpot VMs also usesthe adaptive compiler to decide, on the fly, how best to optimize compiled code with techniques such as in-lining. The runtime analysis performed by the compiler allows it to eliminate guesswork in determining which optimizations will yield the largest performance benefit.+
    [_CLDC HotSpot Implementation Architecture Guide Chapter 4_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/DynamicCompiler.html]
    +Two different compilers are contained in the CLDC HotSpot Implementation virtual machine: an adaptive, just-in-time (JIT) compiler and an ahead-of-time compiler. The JIT compiler is an adaptive compiler, because it uses data gathered at runtime to decide which methods to compile. Only the methods that execute most frequently are compiled. The other methods are interpreted by the virtual machine.+
    [_Java Tuning White Paper_|http://java.sun.com/performance/reference/whitepapers/tuning.html]
    +One of the reasons that it's challenging to measure Java performance is that it changes over time. At startup, the JVM typically spends some time "warming up". Depending on the JVM implementation, it may spend some time in interpreted mode while it is profiled to find the 'hot' methods. When a method gets sufficiently hot, it may be compiled and optimized into native code.+
    [_Frequently Asked Questions About the Java HotSpot VM_|http://java.sun.com/docs/hotspot/HotSpotFAQ.html]
    +Remember how HotSpot works. It starts by running your program with an interpreter. When it discovers that some method is "hot" -- that is, executed a lot, either because it is called a lot or because it contains loops that loop a lot -- it sends that method off to be compiled. After that one of two things will happen, either the next time the method is called the compiled version will be invoked (instead of the interpreted version) or the currently long running loop will be replaced, while still running, with the compiled method. The latter is known as "on stack replacement", or OSR.+
    [_Java Technology Fundamentals Newsletter Index - Making Sense of the Java Classes & Tools: Collection Interfaces, What's New in the Java SE 6 Platform Beta 2, and More_|http://java.sun.com/mailers/newsletters/fundamentals/2006/July06.html]
    +Java: A simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high- performance, multithreaded, dynamic language.+
    [_Introduction to scripting in Java, Part 1_|http://www.javaworld.com/javaworld/jw-07-2007/jw-07-awscripting1.html?page=2]
    +Many of today's interpreted languages are not interpreted purely. Rather, they use a hybrid compiler-interpreter approach, as shown in Figure 1.3.+
    +In this model, the source code is first compiled to some intermediate code (such as Java bytecode), which is then interpreted. This intermediate code is usually designed to be very compact (it has been compressed and optimized). Also, this language is not tied to any specific machine. It is designed for some kind of virtual machine, which could be implemented in software. Basically, the virtual machine represents some kind of processor, whereas this intermediate code (bytecode) could be seen as a machine language for this processor.+
    +This hybrid approach is a compromise between pure interpreted and compiled languages, due to the following characteristics:+
    Because the bytecode is optimized and compact, interpreting overhead is minimized compared with purely interpreted languages.
    The platform independence of interpreted languages is inherited from purely interpreted languages because the intermediate code could be executed on any host with a suitable virtual machine.
    Lately, just-in-time compiler technology has been introduced, which allows developers to compile bytecode to machine-specific code to gain performance similar to compiled languages. I mention this technology throughout the book, where applicable.
    [_Compiled versus interpreted languages_|http://publib.boulder.ibm.com/infocenter/zoslnctr/v1r7/index.jsp?topic=/com.ibm.zappldev.doc/zappldev_85.html]
    Assembler, COBOL, PL/I, C/C++ are all translated by running the source code through a compiler. This results in very efficient code that can be executed any number of times. The overhead for the translation is incurred just once, when the source is compiled; thereafter, it need only be loaded and executed.
    Interpreted languages, in contrast, must be parsed, interpreted, and executed each time the program is run, thereby greatly adding to the cost of running the program. For this reason, interpreted programs are usually less efficient than compiled programs.
    +Some programming languages, such as REXX and Java, can be either interpreted or compiled.+

    Is Java a compiled language?
    Actually, Java is a compiled/interpreted language. See the links below. This is the best classification for the Java language, in my opinion. Read [_this thread_|http://forums.sun.com/thread.jspa?threadID=5320643&start=0&tstart=0] and give your opinion, too! You are very welcome in this interesting discussion. The more I participate in this forum, the more I learn. The more you participate the more you learn, too! Thank you very much for this forum, Sun!
    [_CLDC HotSpot Implementation Architecture Guide Chapter 10_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/VFP.html]
    +The 1.1.3 release of CLDC HotSpot Implementation included limited VFP support. This feature was supported only when running in interpreted mode. In this release, full vector floating point support is provided when the virtual machine is running in compiled mode.+
    [_Java Virtual Machines_|http://java.sun.com/j2se/1.4.2/docs/guide/vm/index.html]
    +Adaptive compiler - Applications are launched using a standard interpreter, but the code is then analyzed as it runs to detect performance bottlenecks, or "hot spots". The Java HotSpot VMs compile those performance-critical portions of the code for a boost in performance, while avoiding unnecessary compilation of seldom-used code (most of the program). The Java HotSpot VMs also usesthe adaptive compiler to decide, on the fly, how best to optimize compiled code with techniques such as in-lining. The runtime analysis performed by the compiler allows it to eliminate guesswork in determining which optimizations will yield the largest performance benefit.+
    [_CLDC HotSpot Implementation Architecture Guide Chapter 4_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/DynamicCompiler.html]
    +Two different compilers are contained in the CLDC HotSpot Implementation virtual machine: an adaptive, just-in-time (JIT) compiler and an ahead-of-time compiler. The JIT compiler is an adaptive compiler, because it uses data gathered at runtime to decide which methods to compile. Only the methods that execute most frequently are compiled. The other methods are interpreted by the virtual machine.+
    [_Java Tuning White Paper_|http://java.sun.com/performance/reference/whitepapers/tuning.html]
    +One of the reasons that it's challenging to measure Java performance is that it changes over time. At startup, the JVM typically spends some time "warming up". Depending on the JVM implementation, it may spend some time in interpreted mode while it is profiled to find the 'hot' methods. When a method gets sufficiently hot, it may be compiled and optimized into native code.+
    [_Frequently Asked Questions About the Java HotSpot VM_|http://java.sun.com/docs/hotspot/HotSpotFAQ.html]
    +Remember how HotSpot works. It starts by running your program with an interpreter. When it discovers that some method is "hot" -- that is, executed a lot, either because it is called a lot or because it contains loops that loop a lot -- it sends that method off to be compiled. After that one of two things will happen, either the next time the method is called the compiled version will be invoked (instead of the interpreted version) or the currently long running loop will be replaced, while still running, with the compiled method. The latter is known as "on stack replacement", or OSR.+
    [_Java Technology Fundamentals Newsletter Index - Making Sense of the Java Classes & Tools: Collection Interfaces, What's New in the Java SE 6 Platform Beta 2, and More_|http://java.sun.com/mailers/newsletters/fundamentals/2006/July06.html]
    +Java: A simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high- performance, multithreaded, dynamic language.+
    [_Introduction to scripting in Java, Part 1_|http://www.javaworld.com/javaworld/jw-07-2007/jw-07-awscripting1.html?page=2]
    +Many of today's interpreted languages are not interpreted purely. Rather, they use a hybrid compiler-interpreter approach, as shown in Figure 1.3.+
    +In this model, the source code is first compiled to some intermediate code (such as Java bytecode), which is then interpreted. This intermediate code is usually designed to be very compact (it has been compressed and optimized). Also, this language is not tied to any specific machine. It is designed for some kind of virtual machine, which could be implemented in software. Basically, the virtual machine represents some kind of processor, whereas this intermediate code (bytecode) could be seen as a machine language for this processor.+
    +This hybrid approach is a compromise between pure interpreted and compiled languages, due to the following characteristics:+
    Because the bytecode is optimized and compact, interpreting overhead is minimized compared with purely interpreted languages.
    The platform independence of interpreted languages is inherited from purely interpreted languages because the intermediate code could be executed on any host with a suitable virtual machine.
    Lately, just-in-time compiler technology has been introduced, which allows developers to compile bytecode to machine-specific code to gain performance similar to compiled languages. I mention this technology throughout the book, where applicable.
    [_Compiled versus interpreted languages_|http://publib.boulder.ibm.com/infocenter/zoslnctr/v1r7/index.jsp?topic=/com.ibm.zappldev.doc/zappldev_85.html]
    Assembler, COBOL, PL/I, C/C++ are all translated by running the source code through a compiler. This results in very efficient code that can be executed any number of times. The overhead for the translation is incurred just once, when the source is compiled; thereafter, it need only be loaded and executed.
    Interpreted languages, in contrast, must be parsed, interpreted, and executed each time the program is run, thereby greatly adding to the cost of running the program. For this reason, interpreted programs are usually less efficient than compiled programs.
    +Some programming languages, such as REXX and Java, can be either interpreted or compiled.+

  • I can�t understand this

    Is Java a compiled language?
    Actually, Java is a compiled/interpreted language. See the links below. This is the best classification for the Java language, in my opinion. Read [_this thread_|http://forums.sun.com/thread.jspa?threadID=5320643&start=0&tstart=0] and give your opinion, too! You are very welcome in this interesting discussion. The more I participate in this forum, the more I learn. The more you participate the more you learn, too! Thank you very much for this forum, Sun!
    [_CLDC HotSpot Implementation Architecture Guide Chapter 10_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/VFP.html]
    +The 1.1.3 release of CLDC HotSpot Implementation included limited VFP support. This feature was supported only when running in interpreted mode. In this release, full vector floating point support is provided when the virtual machine is running in compiled mode.+
    [_Java Virtual Machines_|http://java.sun.com/j2se/1.4.2/docs/guide/vm/index.html]
    +Adaptive compiler - Applications are launched using a standard interpreter, but the code is then analyzed as it runs to detect performance bottlenecks, or "hot spots". The Java HotSpot VMs compile those performance-critical portions of the code for a boost in performance, while avoiding unnecessary compilation of seldom-used code (most of the program). The Java HotSpot VMs also usesthe adaptive compiler to decide, on the fly, how best to optimize compiled code with techniques such as in-lining. The runtime analysis performed by the compiler allows it to eliminate guesswork in determining which optimizations will yield the largest performance benefit.+
    [_CLDC HotSpot Implementation Architecture Guide Chapter 4_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/DynamicCompiler.html]
    +Two different compilers are contained in the CLDC HotSpot Implementation virtual machine: an adaptive, just-in-time (JIT) compiler and an ahead-of-time compiler. The JIT compiler is an adaptive compiler, because it uses data gathered at runtime to decide which methods to compile. Only the methods that execute most frequently are compiled. The other methods are interpreted by the virtual machine.+
    [_Java Tuning White Paper_|http://java.sun.com/performance/reference/whitepapers/tuning.html]
    +One of the reasons that it's challenging to measure Java performance is that it changes over time. At startup, the JVM typically spends some time "warming up". Depending on the JVM implementation, it may spend some time in interpreted mode while it is profiled to find the 'hot' methods. When a method gets sufficiently hot, it may be compiled and optimized into native code.+
    [_Frequently Asked Questions About the Java HotSpot VM_|http://java.sun.com/docs/hotspot/HotSpotFAQ.html]
    +Remember how HotSpot works. It starts by running your program with an interpreter. When it discovers that some method is "hot" -- that is, executed a lot, either because it is called a lot or because it contains loops that loop a lot -- it sends that method off to be compiled. After that one of two things will happen, either the next time the method is called the compiled version will be invoked (instead of the interpreted version) or the currently long running loop will be replaced, while still running, with the compiled method. The latter is known as "on stack replacement", or OSR.+
    [_Java Technology Fundamentals Newsletter Index - Making Sense of the Java Classes & Tools: Collection Interfaces, What's New in the Java SE 6 Platform Beta 2, and More_|http://java.sun.com/mailers/newsletters/fundamentals/2006/July06.html]
    +Java: A simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high- performance, multithreaded, dynamic language.+
    [_Introduction to scripting in Java, Part 1_|http://www.javaworld.com/javaworld/jw-07-2007/jw-07-awscripting1.html?page=2]
    +Many of today's interpreted languages are not interpreted purely. Rather, they use a hybrid compiler-interpreter approach, as shown in Figure 1.3.+
    +In this model, the source code is first compiled to some intermediate code (such as Java bytecode), which is then interpreted. This intermediate code is usually designed to be very compact (it has been compressed and optimized). Also, this language is not tied to any specific machine. It is designed for some kind of virtual machine, which could be implemented in software. Basically, the virtual machine represents some kind of processor, whereas this intermediate code (bytecode) could be seen as a machine language for this processor.+
    +This hybrid approach is a compromise between pure interpreted and compiled languages, due to the following characteristics:+
    Because the bytecode is optimized and compact, interpreting overhead is minimized compared with purely interpreted languages.
    The platform independence of interpreted languages is inherited from purely interpreted languages because the intermediate code could be executed on any host with a suitable virtual machine.
    Lately, just-in-time compiler technology has been introduced, which allows developers to compile bytecode to machine-specific code to gain performance similar to compiled languages. I mention this technology throughout the book, where applicable.
    [_Compiled versus interpreted languages_|http://publib.boulder.ibm.com/infocenter/zoslnctr/v1r7/index.jsp?topic=/com.ibm.zappldev.doc/zappldev_85.html]
    Assembler, COBOL, PL/I, C/C+ are all translated by running the source code through a compiler. This results in very efficient code that can be executed any number of times. The overhead for the translation is incurred just once, when the source is compiled; thereafter, it need only be loaded and executed.+
    Interpreted languages, in contrast, must be parsed, interpreted, and executed each time the program is run, thereby greatly adding to the cost of running the program. For this reason, interpreted programs are usually less efficient than compiled programs.
    +Some programming languages, such as REXX and Java, can be either interpreted or compiled.+

    why this ; after the condition?
    and why do you put else + condition? Maybe you want to put else if?
    try this:
      if (a.length() == 1) {  // I always open and close { } to make my code more readable and avoid errors
        a = "0" + a;
      } else if (a.length() == 3) {
        a = a.substring(1, 3);
      }Hope this helps
    Zerjio

  • Java ME SDK 3.0 Released

    I am happy to announce the Revenue Release of Java Platform Micro Edition Software Development Kit 3.0.
    Java ME SDK includes the advanced tools found in Java Wireless Toolkit 2.5.2 [for CLDC] and Sun Java Toolkit 1.0 [for CDC] and many new features.
    Key Features
    * Integration with third-party emulators and Windows Mobile devices
    * On-device deployment and on-device debugging
    * CLDC/MIDP, CDC/FP/PBP/AGUI, and BD-J integrated into one SDK
    * New CLDC HotSpot Virtual Machine
    * Optimized MSA 1.1 stack with extensions
    * Profiling support
    * Network monitor
    * BD-J support
    * New development environment based on Netbeans Platform
    * Lightweight UI Toolkit (LWUIT) integration
    * Device search database integrated in SDK
    * JavaFX Mobile Emulator included
    Have a look for yourself: [http://java.sun.com/javame/downloads/sdk30.jsp]

    Are there any plans about releasing the SDK on Linux, and if yes, when?

  • Is java a compiled language - part 2

    yamm_v6.6_6 said
    Again, I think you are confusing the compilation process and the interpretation process with the meaning of "compiled language" and "interpreted language", mr. jschell. Compilation process and interpretation process have definitions very well established in the Computer Science, as you said, and I agree with you. There are no controversies in those definitions. On the other hand, the meaning of "compiled language" and "interpreted language" might vary, because in this case there are controversiesNo.
    Compilers are one of the most well studied and well defined aspects of computer science more so than any other part of computer science.
    And the Dragon book is now, and has been for at least 20 years, the recognized authoratative source of that part of computer science.
    And there is nothing in there that supports your conclusion nor nothing that supports your term definitions.
    A language in of itself is never compiled nor interpreted. That book specifically defines the process under which a language must be processed to become either compiled and/or interpreted.
    If you wish to disagree with that then state something from that book or first demonstrate that that book is no longer the authorative source.
    Finally note that in terms of computer science none of the java documents (specifications or otherwise) are suitable authoratative sources. The java specifications although adequate are far from precise in the adherence to definitions in computer science, or even in the definition of java itself.

    Wow! I was just googling, and then look at what I found! This thread! Thanks, mr jschell, for your replies. I really appreciate them.
    jschell wrote:
    Finally note that in terms of computer science none of the java documents (specifications or otherwise) are suitable authoratative sources. The java specifications although adequate are far from precise in the adherence to definitions in computer science, or even in the definition of java itself.Well, do you want authoritative sources, right? How about this:
    [_CLDC HotSpot Implementation Architecture Guide Chapter 10_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc[_CLDC HotSpot Implementation Architecture Guide Chapter 10_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/VFP.html]
    +The 1.1.3 release of CLDC HotSpot Implementation included limited VFP support. This feature was supported only when running in interpreted mode. In this release, full vector floating point support is provided when the virtual machine is running in compiled mode.+
    [_Java Virtual Machines_|http://java.sun.com/j2se/1.4.2/docs/guide/vm/index.html]
    +Adaptive compiler - Applications are launched using a standard interpreter, but the code is then analyzed as it runs to detect performance bottlenecks, or "hot spots". The Java HotSpot VMs compile those performance-critical portions of the code for a boost in performance, while avoiding unnecessary compilation of seldom-used code (most of the program). The Java HotSpot VMs also usesthe adaptive compiler to decide, on the fly, how best to optimize compiled code with techniques such as in-lining. The runtime analysis performed by the compiler allows it to eliminate guesswork in determining which optimizations will yield the largest performance benefit.+
    [_CLDC HotSpot Implementation Architecture Guide Chapter 4_|http://java.sun.com/javame/reference/docs/cldc-hi-2.0-web/doc/architecture/html/DynamicCompiler.html]
    +Two different compilers are contained in the CLDC HotSpot Implementation virtual machine: an adaptive, just-in-time (JIT) compiler and an ahead-of-time compiler. The JIT compiler is an adaptive compiler, because it uses data gathered at runtime to decide which methods to compile. Only the methods that execute most frequently are compiled. The other methods are interpreted by the virtual machine.+
    [_Java Tuning White Paper_|http://java.sun.com/performance/reference/whitepapers/tuning.html]
    +One of the reasons that it's challenging to measure Java performance is that it changes over time. At startup, the JVM typically spends some time "warming up". Depending on the JVM implementation, it may spend some time in interpreted mode while it is profiled to find the 'hot' methods. When a method gets sufficiently hot, it may be compiled and optimized into native code.+
    [_Frequently Asked Questions About the Java HotSpot VM_|http://java.sun.com/docs/hotspot/HotSpotFAQ.html]
    +Remember how HotSpot works. It starts by running your program with an interpreter. When it discovers that some method is "hot" -- that is, executed a lot, either because it is called a lot or because it contains loops that loop a lot -- it sends that method off to be compiled. After that one of two things will happen, either the next time the method is called the compiled version will be invoked (instead of the interpreted version) or the currently long running loop will be replaced, while still running, with the compiled method. The latter is known as "on stack replacement", or OSR.+
    [_Java Technology Fundamentals Newsletter Index - Making Sense of the Java Classes & Tools: Collection Interfaces, What's New in the Java SE 6 Platform Beta 2, and More_|http://java.sun.com/mailers/newsletters/fundamentals/2006/July06.html]
    +Java: A simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high- performance, multithreaded, dynamic language.+

  • WL 8.14 on Solaris 9 not using Native I/O

    We are attempting to convert an application from Hotspot to JRockit R27.1.0-jdk1.4.2_12 on WebLogic 8.14 under Solaris 9. JRockit does not seem to be able to use the native I/O feature as did Hotspot. Is this a known problem or is there something else that has to change in the port from Hotspot to JRockit?
    Thanks,
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