http://www.sagewire.org/Blogs and forums for Java, PHP, MySQL, and more.enhttp://www.sagewire.org/java-machine/JVM-vs-NET-1965500.aspxI'm relatively new to both the JVM and .NET and am learning Scala and F#. I was under the impression that .NET was essentially a later and greater reimplementation of the JVM in a Windows-specific form. However, I have just discovered some nasty caveats in .NET. Specifically, if you generate and use regular expressions the obvious way then .NET leaks memory because it performs run-time compilation to improve performance but fails to garbage collect the generated code when it is no longe...http://www.sagewire.org/java-machine/JVM-vs-NET-1965500.aspxrss@sagewire.orgFri, 12 Oct 2007 21:41:50 GMThttp://www.sagewire.org/java-machine/Optimization-question-1943752.aspxHi All, Quick question about optimizing JVM bytecode. Suppose I have the following JAVA code: public static void main(String[] args) { int a[] = new int[42]; for (int i=0; I < a.length; ++i) a[i] = 1; int sum = 0; for (int i=0; I < a.length; ++i) sum = sum + a[i] ; System.out.println(sum); } wrote in message an optimizer that pre-evaluated the code and just generated byte-code that output the value 42? In other words, didn't even bother allocating the arra...http://www.sagewire.org/java-machine/Optimization-question-1943752.aspxrss@sagewire.orgFri, 28 Sep 2007 02:06:08 GMThttp://www.sagewire.org/java-machine/Questions-about-JAVA-VM-spec-1939615.aspx1. Why does not the JAVA 6 link to the VM spec include the addendum to the class file format that has all of the stack trace information? The only place I can find it is through the actual JSR... 2. When is the SourceDebugExtension attribute actually used? 3. What is the difference in purpose between invokevirtual and invokeinterface ? Answers'd be much obliged. -- Beware of bugs in the above code; I have only proved it correct, not tried it. -- Donald E. Knuthhttp://www.sagewire.org/java-machine/Questions-about-JAVA-VM-spec-1939615.aspxrss@sagewire.orgFri, 21 Sep 2007 02:38:51 GMThttp://www.sagewire.org/java-machine/Synchronized-implementations-1929655.aspxI haven'ticed a few times that JAVA implements synchronized blocks thusly: aload 4 dup astore 5 monitorenter [ various instructions ] aload 5 monitorexit Why does it duplicate the variable when running synchronized blocks? -- Beware of bugs in the above code; I have only proved it correct, not tried it. -- Donald E. Knuthhttp://www.sagewire.org/java-machine/Synchronized-implementations-1929655.aspxrss@sagewire.orgThu, 13 Sep 2007 08:33:33 GMThttp://www.sagewire.org/java-machine/Cannot-delete-Se-Development-Kit-from-Vista-1922954.aspxHello, I need to reinstall the JDK but the installer insists the development kit is still installed, when I agree to re-installing it just stays in an endless loop of telling me it is already installed and do I want to reinstall. I have physically deleted all the JAVA directories and last night paid 40 bucks for a registry cleaner that has made no difference. When I try to delete using the uninstall utility in Vista it claims to delete it by the JAVA SE Development Kit Update 2 ref...http://www.sagewire.org/java-machine/Cannot-delete-Se-Development-Kit-from-Vista-1922954.aspxrss@sagewire.orgSat, 08 Sep 2007 05:32:02 GMThttp://www.sagewire.org/java-machine/HotSpot-crashed-on-Linux-1855794.aspxThe HotSpot JVM was running Tomcat, which hosted our web application in the production environment. It had been restarted 6 days ago and had been running fine since. And the same JVM+application usually work fine, we've used them for months, restarting from time to time, and never had this problem. In the JVM error file, I notice about 5000 threads, could this be a problem ? Is the HotSpot JVM unable to handle many threads ? Should I change the way my application uses threads ? Cou...http://www.sagewire.org/java-machine/HotSpot-crashed-on-Linux-1855794.aspxrss@sagewire.orgWed, 25 Jul 2007 19:30:53 GMThttp://www.sagewire.org/java-machine/Weird-entry-in-the-exception-table-for-monitorente-1857109.aspxI have created a simple test class with one method: public class TestClass { int a = 0; public void test() { synchronized(TestClass.class) { a = 1; } } } After opening the generated class file with Eclipse I got the next result (I have removed the parts that are irrelevant) public void test(); 0 ldc [code]<Class TestClass>[/code] [1] 2 dup 3 astore_1 4 monitorenter 5 aload_0 [this] 6 iconst_1 7 putfield TestClass...http://www.sagewire.org/java-machine/Weird-entry-in-the-exception-table-for-monitorente-1857109.aspxrss@sagewire.orgThu, 19 Jul 2007 00:53:00 GMThttp://www.sagewire.org/java-machine/JAVA-virtual-machine-help-me-please-1819979.aspxHello All, I have installed jre1.4.2_14 and I have been trying to get a small "hello world type" program to run. Once I got jre installed, I open my dos window and changed directories to folder on on my local drive that contains the jave program. I then try to run it by typeing JAVAc aus.JAVA. The error message does not recognize the command. However, when I type JAVA the error says that it cannot find Main string in JAVA.lang [code]<-- I do not have full message because I am currently a...http://www.sagewire.org/java-machine/JAVA-virtual-machine-help-me-please-1819979.aspxrss@sagewire.orgFri, 15 Jun 2007 16:17:06 GMThttp://www.sagewire.org/java-machine/JVM-for-research-1819768.aspxI am reading the book "In side the JVM", and very interested in the internals of JVM. I want to find a simple JVM to read the code. Is there any good JVM for research? I have looked at kaffe, but not sure it is suitable for research or not. -- Yao Qi [code]<qiyaoltc@xxxxxxxxxxx>[/code] GNU/Linux Developer http://duewayqi.googlepages.com/http://www.sagewire.org/java-machine/JVM-for-research-1819768.aspxrss@sagewire.orgFri, 15 Jun 2007 16:00:05 GMThttp://www.sagewire.org/java-machine/Heap-and-Memory-Footprint-1754354.aspxI used JProf to see that my Swing app has 40 megs of heap allocated to it. However, over time VM size of the JAVA.exe process keeps on rising and at times hits 300 megs. I understand that the JVM may be using this memory for internal purposes. But is there a way to limit the size to which the VM grows? In short if I need to tell my customers that when they run my app the VM size won't grow higher than some limit. Are there any VM parameters I can use to ensure this.http://www.sagewire.org/java-machine/Heap-and-Memory-Footprint-1754354.aspxrss@sagewire.orgMon, 11 Jun 2007 21:05:24 GMThttp://www.sagewire.org/java-machine/JAVAc-generates-bytecode-using-an-inner-class-but-1805992.aspxThis here came up on the Soot mailing list... (see http://www.sable.mcgill.ca/pipermail/soot-list/2007-June/001238.html). It'd be great if you could comment on the problem if you know of anything that could be helpful. I have a problem with inner classes, in particular the way JAVAc generates them. Assume you've the following small JAVA source example: ======== public class SootProblem { public SootProblem() { if (false) { Runnable myRunnable = ...http://www.sagewire.org/java-machine/JAVAc-generates-bytecode-using-an-inner-class-but-1805992.aspxrss@sagewire.orgSat, 02 Jun 2007 21:47:54 GMThttp://www.sagewire.org/java-machine/65535-bytes-method-code-limit-384885.aspxI'm getting: "The code of method mTokens() is exceeding the 65535 bytes limit" The method is antlr generated, so I struggle to find any workaround. Perhaps I'm missing some magic JVM parameter setting? Are not 16 bit integers relics of the past century?http://www.sagewire.org/java-machine/65535-bytes-method-code-limit-384885.aspxrss@sagewire.orgThu, 31 May 2007 21:48:57 GMThttp://www.sagewire.org/java-machine/Manipulate-JAVA-thread-stack-in-this-way-1640144.aspxWe are doing byte code instrumentation, and at one moment (before call a method, o.f(long);), the stack layout of our program thread is shown as follows, top--> +--------+ | long | +--------+ | Object | +--------+ | ... | we want to transform this stack layout to this, shown as follows, top--> +--------+ | Object | +--------+ | long | +--------+ ...http://www.sagewire.org/java-machine/Manipulate-JAVA-thread-stack-in-this-way-1640144.aspxrss@sagewire.orgMon, 28 May 2007 22:25:02 GMThttp://www.sagewire.org/java-machine/TFIDF-algorithm-in-JAVA-1056968.aspxhi every body I need help to make a program in JAVA programming language to make TF- IDF algorithm which is one algorithm for rank pages please help mehttp://www.sagewire.org/java-machine/TFIDF-algorithm-in-JAVA-1056968.aspxrss@sagewire.orgFri, 27 Apr 2007 23:31:43 GMThttp://www.sagewire.org/java-machine/Higher-Order-ByteCode-Instructions-691237.aspxI was wondering if there has been any research into adding higher- order instruction to the JAVA bytecode? In other words instructions that either push or pop instructions on the evaluation stack. There are only a few core instructions that'd be neccessary to build others : - constantly : pop a value, push an instruction on the stack that returns that value - compose : pop two instructions, push a new instruction that evaluates the first function, then the second. - eval : pop an in...http://www.sagewire.org/java-machine/Higher-Order-ByteCode-Instructions-691237.aspxrss@sagewire.orgWed, 11 Apr 2007 15:56:44 GMThttp://www.sagewire.org/java-machine/How-do-get-smooth-handwriting-on-Tablet-PC-using-389075.aspxI've written a distributed presentation/whiteboarding application (JAVA2/Swing) for online-tutoring. Currently I use a graphics tablet to draw and write on the whiteboard. Now I'd like to switch from using a separate graphics tablet to using the stylus of a Tablet PC. However, my JAVA application seems to drop a great many mouse drag events, which results in hardly legible handwriting (not so with native Tablet PC applications like Windows Journal). http://www.freesoft.org/software...http://www.sagewire.org/java-machine/How-do-get-smooth-handwriting-on-Tablet-PC-using-389075.aspxrss@sagewire.orgTue, 03 Apr 2007 16:27:28 GMThttp://www.sagewire.org/java-machine/Adding-constructor-by-bytecode-instrumentation-389675.aspxHello, I am trying to use JVMTI to instrument the bytecode of all classes up to JAVA.lang.Object. I need this so I can have a plain constructor (with some special signature) that doesn't do anything besides calling a superclass constructor that also doesn'thing (I want to simulate the effect of the actual constructor later). Right now, that doesn't sound too complicated to me: add another [code]<init>[/code] method in the constant pool and a method block later. However, before I start, ...http://www.sagewire.org/java-machine/Adding-constructor-by-bytecode-instrumentation-389675.aspxrss@sagewire.orgThu, 29 Mar 2007 20:23:19 GMThttp://www.sagewire.org/java-machine/modifying-JAVAlangStringJAVA-391067.aspxHi, I'm trying to modify JAVA.lang.String.JAVA and add the modified String.class to rt.jar [THIS IS FOR MYSELF ONLY AND won't BE DEPLOYED]. I cannot add "private final boolean tainted[] = new boolean[5];" to String.JAVA. If I do, it still compiles and I can add it to rt.jar and compile a test program against it. However, the JVM crashes with a strange message: JAVA.lang.IllegalArgumentException: name can not be empty at JAVA.security.BasicPermission.init(Unknown Source) ...http://www.sagewire.org/java-machine/modifying-JAVAlangStringJAVA-391067.aspxrss@sagewire.orgMon, 26 Mar 2007 13:49:45 GMThttp://www.sagewire.org/java-machine/Connect-to-JAVA-application-from-JAVA-login-form-388797.aspxGood Day! Would be appreciate to know any suggestion on the following coding problem: Originally, I've a JAVA application. Now, I've developed a JAVA login form which is name as Login.JAVA Would be appreciate to know how to compose the code to link to the JAVA application after the user successful login. Both JAVA source files (including the JAVA application) are stored at http://tech.groups.yahoo.com/group/JAVAlogin/ Please refer the source file and suggest. Thanks for a...http://www.sagewire.org/java-machine/Connect-to-JAVA-application-from-JAVA-login-form-388797.aspxrss@sagewire.orgFri, 16 Mar 2007 21:13:02 GMThttp://www.sagewire.org/java-machine/JDK-14205-375255.aspxI use WebLogic 8.1 on a Solaris 9 box with 8 processors. I've JDK 1.4.2_05 installed and due to long pauses with the default collector, I tried out the Concurrent garbage collector. However, once I do that, the system runs out of file handles within minutes of starting the load test. Solaris is setup with 8192 as the top limit for file handles. I tried various options within Concurrent garbage collector (like ParNewGC, CMSParallelRemark) but all lead to system running out of file handle...http://www.sagewire.org/java-machine/JDK-14205-375255.aspxrss@sagewire.orgMon, 19 Feb 2007 15:16:06 GMThttp://www.sagewire.org/java-machine/JVM-errors-375336.aspxHi, I am getting the following error when I execute the a particular query that returns 34 records. However, each row has lots of columns. If I reduce the number of rows or the number of columns the error goes away. I don't get this error on Windows XP, even when I do not reduce the number of rows/columns. (JAVA version "1.5.0_09") JAVA(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_09-b01) JAVA HotSpot(TM) Client VM (build 1.5.0_09-b01, mixed mode) Only on Linux.(1.5.0_06-...http://www.sagewire.org/java-machine/JVM-errors-375336.aspxrss@sagewire.orgMon, 19 Feb 2007 15:00:47 GMThttp://www.sagewire.org/java-machine/Keyword-extractors-source-codewhere-can-find-it-371407.aspxHi,sorry for my english but I do not speak it very well.... Someone knows where I can find the Keyword Extractor source code written in JAVA? A software that analyzes a text and extract the keyword of the text (the most present words in the text....for example the word "hello" is present forty times,the word "thanks" is present thirty times....). I need to see the software's source code written in JAVA in order to understand as it works.... Thaks,byehttp://www.sagewire.org/java-machine/Keyword-extractors-source-codewhere-can-find-it-371407.aspxrss@sagewire.orgWed, 17 Jan 2007 09:25:31 GMThttp://www.sagewire.org/java-machine/jvmgarbage-collection-project-idea-365334.aspxCan anyone suggest me a good project idea on jvm, garbage collection , etc I've knowledge of - (1) C/C++ , lex,yacc (2) x86 assembly (3) Linux memory management (4) jvm architecture thank you,http://www.sagewire.org/java-machine/jvmgarbage-collection-project-idea-365334.aspxrss@sagewire.orgThu, 14 Dec 2006 13:42:09 GMThttp://www.sagewire.org/java-machine/JAVA-VM-for-WindowsCE-Pocket-PC-356050.aspxHi all, at our university we are working on a project to implement a Mobile-AdHoc-Network-Router on PocketPCs running WindowsCE. We'd prefer to use JAVA for our development, however we were unable to find a suitable VM for that platform. We don't need fancy things like UI-toolkits, no need for Swing, AWT, SWT,... It'd be nice though if we could've a decent and solid J2SE VM (preferably >= 1.4). Any hints are really appreciated - no matter if it's a commercial or free VM.Thank y...http://www.sagewire.org/java-machine/JAVA-VM-for-WindowsCE-Pocket-PC-356050.aspxrss@sagewire.orgTue, 28 Nov 2006 17:03:42 GMThttp://www.sagewire.org/java-machine/JNI-CallStaticVoidMethod-fails-after-calls-359211.aspxI've written an application in JAVA and C on the Solaris 10 (x86) platform using the JDK 1.5.0_09. The JAVA code calls a native method "startButtonWatcher," which then forks, the parent process returning, and the child process initiating an event loop that calls a static method, "sendButtonEvent," on a JAVA class "ButtonWatcher." The problem is that on the 65 invocation, the CallStaticVoidMethod will hang. There is no core file or pid log file produced. (it'll also hang for CallVoidMeth...http://www.sagewire.org/java-machine/JNI-CallStaticVoidMethod-fails-after-calls-359211.aspxrss@sagewire.orgThu, 23 Nov 2006 11:41:20 GMThttp://www.sagewire.org/java-machine/JNICreateJAVAVM-fails-359555.aspxHello, I try to create a JAVA virtual machine in a C++ application (Windows XP). I've installed jdk1.5.0_08 and I am sure, that my application loads the appropriate jvm.dll. Here is my simple code, I receive always -1: ... JAVAVMOption options[2]; options[0].optionString = "-DJAVA.compiler=NONE"; options[1].optionString = "-DJAVA.class.path=."; JAVAVMInitArgs args; args.version = JNI_VERSION_1_4; args.nOptions = 2; args.options = options; args.ignoreUnrecognized = JNI...http://www.sagewire.org/java-machine/JNICreateJAVAVM-fails-359555.aspxrss@sagewire.orgWed, 22 Nov 2006 16:12:09 GMThttp://www.sagewire.org/java-machine/JNIGetCreatedJAVAVMs-fails-359526.aspxHello, I try to start a JAVA virtual machine from a C++ application (Windows XP). I've 'jdk1.5.0_08' installed and I am sure, that my application loads the appropriate jvm.dll. Here is my simple code, I receive always -1: ... JAVAVMOption options[2]; options[0].optionString = "-DJAVA.compiler=NONE"; options[1].optionString = "-DJAVA.class.path=."; JAVAVMInitArgs args; args.version = JNI_VERSION_1_4; args.nOptions = 2; args.options = options; args.ignoreUnrecognized = ...http://www.sagewire.org/java-machine/JNIGetCreatedJAVAVMs-fails-359526.aspxrss@sagewire.orgWed, 22 Nov 2006 14:46:40 GMThttp://www.sagewire.org/java-machine/JAVA-slow-356135.aspxHi I was thinking about learning the JAVA programing language. I asked a friend his views and he told me not to bother - as JAVA is a slow piece of shit ! Is that true, is it really a goofy outdated language that doesnt run quickly like other languages? (from the horses month). Thankshttp://www.sagewire.org/java-machine/JAVA-slow-356135.aspxrss@sagewire.orgTue, 21 Nov 2006 09:20:13 GMThttp://www.sagewire.org/java-machine/Error-building-app-356724.aspxI am having problem while building app. For some reason it stopped working. I had a pretty bad crash and lost a lot of stuff. Since then, borland jbuilder doesn't want to properly compile. I am getting this error message: "Application1.JAVA": Error #: 750 : initialization error: com.borland.compiler.symtab.LoadError: neither class nor source found for JAVA.lang.Object Any help'd be appreciated.http://www.sagewire.org/java-machine/Error-building-app-356724.aspxrss@sagewire.orgSat, 11 Nov 2006 08:18:15 GMThttp://www.sagewire.org/java-machine/Testing-single-core-processor-in-JAVA-352762.aspxHi all, I delevoped multi-threaded application and I'd like to test it on: - machine with 2-cored processor - machine with 2 processors Is there possibility to push JVM to use only one core / one processor of hosting machine ? Just for comparision of efficiency ? Regards, Maciejhttp://www.sagewire.org/java-machine/Testing-single-core-processor-in-JAVA-352762.aspxrss@sagewire.orgFri, 27 Oct 2006 14:06:22 GMThttp://www.sagewire.org/java-machine/IBM-WEME-J2ME-CDC-on-Motorola-352090.aspxHello -- I recently installed IBM's WEME J2ME CDC implementation, version 6.1, on a Motorola Q. When I tried to run the GolfScoreTracker application, I got an OutOfMemoryError. I fixed this by adding the parameter "Xmx64m" to the link file. Now when I run the app, the error I get is NoClassDefFound, except that when it appears in the J9 Console it says "NoClassD". I can not scroll the console window across to see which class it can not find. Does anyone one know how to make the t...http://www.sagewire.org/java-machine/IBM-WEME-J2ME-CDC-on-Motorola-352090.aspxrss@sagewire.orgThu, 26 Oct 2006 15:14:05 GMThttp://www.sagewire.org/java-machine/Maximizing-Server-Memory-Windows-2003-Server-5GB-R-344019.aspxI am running Jboss 4.0.1sp1 with the 1.4.2_10 JVM on a Windows 2003 Server with 5GB RAM. I'd like to run multiple instances of Jboss, giving each 2GB available RAM to work with leaving the remaining 1GB for the OS. Is the above scenario fairly standard? Do I need to do any special configuration to allow this to happen? Can you point me to a reference link with some documentation around server memory with multiple instances? Thanks in advance...http://www.sagewire.org/java-machine/Maximizing-Server-Memory-Windows-2003-Server-5GB-R-344019.aspxrss@sagewire.orgTue, 26 Sep 2006 14:23:55 GMThttp://www.sagewire.org/java-machine/Display-Default-Heap-Size-342481.aspxHi all - I have scoured the internet for this and can not find any helpful information. Is there any way for the JVM to display the default maximum heap size on a system? I can not seem to figure out what it is using as its maximum value, if I do not manually override it with -Xmx. Any help'd be really appreciated. Thanks - Aaronhttp://www.sagewire.org/java-machine/Display-Default-Heap-Size-342481.aspxrss@sagewire.orgWed, 20 Sep 2006 21:48:39 GMThttp://www.sagewire.org/java-machine/Exist-JAVA-for-ARM-microprocessors-340184.aspxas in title any links, docs, contacts regards Martinhttp://www.sagewire.org/java-machine/Exist-JAVA-for-ARM-microprocessors-340184.aspxrss@sagewire.orgSun, 17 Sep 2006 01:56:29 GMThttp://www.sagewire.org/java-machine/Exception-in-thread-CompilerThread0-JAVAlangOutOfM-324963.aspxI get the following error when running my application using JDK 1.4.2_07 on a Debian Linux box. Exception in thread "CompilerThread0" JAVA.lang.OutOfMemoryError: requested 1634084 bytes for Chunk::new. Out of swap space? The JVM has been allocated a max of 1.5GB of heap and the system itself has 3GB of physical memory. The JVM crashes randomly and the system seems to have enouugh physical memory and swap space when this happens. Some of the other params that are relevant here are : ...http://www.sagewire.org/java-machine/Exception-in-thread-CompilerThread0-JAVAlangOutOfM-324963.aspxrss@sagewire.orgWed, 30 Aug 2006 14:53:28 GMThttp://www.sagewire.org/java-machine/join-forum-discussJAVAcomforum-336482.aspxHi, I've created a forum and a website that isn't completely done but free. The forum is basicly JAVA people helping each other and the website is geared towards having contests created by the users and job recruiters. thanks join forum discussJAVA.com/forumhttp://www.sagewire.org/java-machine/join-forum-discussJAVAcomforum-336482.aspxrss@sagewire.orgMon, 28 Aug 2006 13:45:53 GMThttp://www.sagewire.org/java-machine/argument-of-invokevirtual-335011.aspxHi. While I'm writing codes on call graph construction of JAVA programs, I have got a question. I'm wondering how the class name in the argument of invokevirtual is determined. Is it the name of a class containing the method definition? The code snippet (1) is compiled into the bytecode (2). Neither printStackTrace() nor equals() aren't defined in the AWTException. But the class name of the first invokevirtual is AWTException, whereas the class name of the second invokevirtual is Obj...http://www.sagewire.org/java-machine/argument-of-invokevirtual-335011.aspxrss@sagewire.orgTue, 22 Aug 2006 16:09:06 GMThttp://www.sagewire.org/java-machine/JAVA-VM-Question-239993.aspxI've a JAVA web application running on Sun Solaris 10 platform, the JAVA version is 1.5.0. Recently I found when I used TOP command to get the memory used by my application it was over 1.5GB and kept increasing. However when using the JAVA.lang.Runtime.totalMemory() and freeMemory() methods from my code the memory usage was way lower than the size reported by TOP. From totalMemory() and freeMemory() method calls I could see that there didn't seem to have a memory leak in my code and the ...http://www.sagewire.org/java-machine/JAVA-VM-Question-239993.aspxrss@sagewire.orgSat, 19 Aug 2006 14:50:28 GMThttp://www.sagewire.org/java-machine/JIT-compilers-docs-235479.aspxHi All ! Can anybody point me on the good documentation about common principies and keys aspects of realisation of JIT compilers ? -- dimahttp://www.sagewire.org/java-machine/JIT-compilers-docs-235479.aspxrss@sagewire.orgThu, 27 Jul 2006 16:12:36 GMThttp://www.sagewire.org/java-machine/JAVA-collection-problem-235476.aspxHi everyone, I need to have alarge array of small class'es (in c# sense struct). For premitive types, as the ArrayList stores value types, hence it is possible to use apache common primitives library to save memory & cache overflow. However, for array of classes, which are small enough, I want to store them as value, so that they occupy contiguous memory space, rether than heving them referenced from list. This is just to decrease cache overflow error & speedup things. Is the...http://www.sagewire.org/java-machine/JAVA-collection-problem-235476.aspxrss@sagewire.orgTue, 25 Jul 2006 18:44:59 GMThttp://www.sagewire.org/java-machine/JVM-fails-to-use-more-than-one-CPUcore-on-235477.aspxWe're using the Sun 1.5.0_06 JVM on RedHat (AS). The box has 4 CPUs, they're all available and get some load (i. e. OS recognized them and they work). But al our JVM max out by just "digesting" a single CPU, i. e. any JVM maxes out at 25% of the system load. Using a simple CPU-eater program that runs multiple thread I was able to: - "digest" 2 cores on Win XP - "digest" 2 cores on Max OS X (Intel) - still only 1 (!) CU on the Linux server Where's the problem? Anyone else having the ...http://www.sagewire.org/java-machine/JVM-fails-to-use-more-than-one-CPUcore-on-235477.aspxrss@sagewire.orgTue, 25 Jul 2006 08:26:04 GMThttp://www.sagewire.org/java-machine/Alternative-to-JVM-235473.aspxIs there any alternative to JVM exists as research product, like a 2 address or 3 address instruction set VM ? Ofcourse it won't be able to compile class file, but can run JAVA program with help of a different compiler, which will compile JAVA to a 2-address / 3-address instruction code based class. I am specially interested if some compiler compiles JAVA to DLX processor... I am not looking for a commercial product, even any research implementation or a IEEE/ ACM paper will help me ......http://www.sagewire.org/java-machine/Alternative-to-JVM-235473.aspxrss@sagewire.orgWed, 19 Jul 2006 18:14:52 GMThttp://www.sagewire.org/java-machine/Polymorphism-in-JAVA-61622.aspxHi Friends, Do not missout on these articles on design techniques: Polymorphism in JAVA: http://JAVAlive.com/modules/articles/article.php?id=19 The Factory Design Pattern: http://JAVAlive.com/modules/articles/article.php?id=18 Effective use of Interfaces and Abstract Classes: http://JAVAlive.com/modules/articles/article.php?id=17 Why ORM Tools aren't Recommended: http://JAVAlive.com/modules/articles/article.php?id=16 How to Estimate Project Deadlines: http://JAVAlive.com/m...http://www.sagewire.org/java-machine/Polymorphism-in-JAVA-61622.aspxrss@sagewire.orgSat, 15 Jul 2006 01:38:42 GMThttp://www.sagewire.org/java-machine/Strange-applet-behavior-119684.aspxMy applet works correctly for most users but some users are complaining that on certain machines it takes about 90 seconds to loads whereas normally it takes only about 2-3 seconds. What could be causing this behavior? I do not have access to those machines to examine since they have confidential data.http://www.sagewire.org/java-machine/Strange-applet-behavior-119684.aspxrss@sagewire.orgThu, 06 Jul 2006 14:59:15 GMThttp://www.sagewire.org/java-machine/Bernd-Paysans-B16-VLIW-protocol-experiment-61625.aspx--- 0 1 2 3 4 5 6 7 Comment 0 nop call jmp ret jz jnz jc jnc destination in rest of instruction nop exec goto ret gz gnz gc gnc for slot 3 8 xor com and or + +c *+ /- 10 A!+ A@+ X@+ ext1 >X >Y Y!- lit A! A@ X ext2 X> Y> Y!+ lit for slot 1 18 nip drop over dup >r >a r> a ---http://www.sagewire.org/java-machine/Bernd-Paysans-B16-VLIW-protocol-experiment-61625.aspxrss@sagewire.orgMon, 26 Jun 2006 00:19:05 GMThttp://www.sagewire.org/java-machine/Which-JAVA-version-to-target-61621.aspxAre there any up-to-date statistics available that give a good idea of what JAVA version most web users have installed on their machines? I'm developing a JAVA applet as part of a web site, and I'd like to know that most users will be able to view it without any issues - as it is, if I compile it to target JDK 1.5, all the machines other than my own that I have tested it on won't load the applet, and worse still, do not give any sensible user feedback as to why. I accept there will als...http://www.sagewire.org/java-machine/Which-JAVA-version-to-target-61621.aspxrss@sagewire.orgWed, 21 Jun 2006 12:10:11 GMThttp://www.sagewire.org/java-machine/64bit-JVM-for-Linux-on-Intel-61623.aspxHi, I'm looking for a 64-bit JVM for Linux on Intel, but it looks like Sun does not offer one. Am I just missing it, or are there really no 64-bit JVMs for Linux on Intel? Are there free alternatives? Thanks.http://www.sagewire.org/java-machine/64bit-JVM-for-Linux-on-Intel-61623.aspxrss@sagewire.orgWed, 21 Jun 2006 10:18:11 GMThttp://www.sagewire.org/java-machine/Disabling-hotspotoptimisations-61619.aspxIs it possible to disable runtime optimisations (inlining, compilation, and whatever else goes on) on modern *sun* JVMs (>= 1.4)? -classic has been gone since 1.4 so how does one disable hotspot these days? -Xint isnt quite the same thing ... is it? Thanks.http://www.sagewire.org/java-machine/Disabling-hotspotoptimisations-61619.aspxrss@sagewire.orgWed, 17 May 2006 07:38:14 GMThttp://www.sagewire.org/java-machine/Many-threads-and-OutOfMemoryError-JAVA-heap-size-61617.aspxHi, I've an application with about 1500 threads and a PC with 1 GB RAM. I start the application with following vm arguments: -Xms512m -Xmx512m -Xss64k, but still getting the OutOfMemoryError: JAVA heap size for threads. Maybe somebody knows a tool which could help me to locate the problem? Or anybody has maybe any idea why it happens? jacekhttp://www.sagewire.org/java-machine/Many-threads-and-OutOfMemoryError-JAVA-heap-size-61617.aspxrss@sagewire.orgTue, 16 May 2006 12:07:16 GMThttp://www.sagewire.org/java-machine/What-FPU-intructions-JDK-support-61615.aspxAnyone knows if jdk does support FPU instructions? I'm particularly interested in atan and exp functions.. I have googled around for a time but did not found anything of specific Thanks Dimitrihttp://www.sagewire.org/java-machine/What-FPU-intructions-JDK-support-61615.aspxrss@sagewire.orgWed, 03 May 2006 12:37:25 GMT