Java Virtual Machine Internals
Hey, Can u suggest some articles or books about JVM internals: how it allocates memory, handles object inheritance, garbage collection, how it executes byte code and so on. ...
jvm
Java bytecode compiler benchmarks
Q.1. What free compiler produces the most optimal Java bytecode? Q.2. What free virtual machine executes Java bytecode the fastest (on 64-bit multi-core CPUs)? Q.3. What other (currently active) compiler projects are missing from this list: http://www.ibm.com/developerworks/java/jdk/ http://gcc.gnu.org/java/ http://openjdk.java.net/g...
Increasing the JVM maximum heap size for memory intensive applications
I need to run a Java memory intensive application that uses more than 2GB, but I am having problems to increase the heap maximum size. So far, I have tried the following approaches: Setting the -Xmx parameter, e.g. -Xmx3000m. This approaches fails at the creation of the JVM. From what I've googled, it looks like that -Xmx must be less ...
Which memory related Tomcat JVM startup parameters are worth tuning?
I'm trying to understand the fine art of tuning Tomcat memory settings. In this quest I have the following three questions: Which memory related JVM startup parameters are worth setting when running Tomcat? Why? What are useful rule-of-thumbs when fine-tuning the memory settings for a Tomcat installation? How do you monitor the memory...
JVM performance test suite
Hi, I have just ported phoneME to our MIPS platform. I feel it runs not that fast; however, is there any performance test suite I can run against to get some quantitative measurement of the performance? I might need to pick some weak points for optimization. In addition, what are common criterions used to evalute a JVM ? ...
CPU Usage (%) MBean on Sun JVM
The overview tab of a process on jconsole shows me the CPU Usage percentage. Is there a MBean that gives me this value? What is its ObjectName? ...
JVM tuning on Amazon EC2
We will be deploying a production application to Amazon EC2 very shortly. Initially, we'll just be using a "small" instance, but have plans to scale up not long afterwards. My question is, has any investigation been done on JVM tuning for the EC2 environment? Are there any specific changes that we should make to our JVM parameters to ...
Java respawn process
I'm making an editor-like program. If the user chooses File->Open in the main window I want to start a new copy of the editor process with the chosen filename as an argument. However, for that I need to know what command was used to start the first process: java -jar myapp.jar blabalsomearguments // --- need this information > Open File...
IBM i (AS400) updates on new Java releases / Java 7
Since Java 7 is comming I was wondering how much time it would take to have the IBM JVM running Java 7 on IBM i systems? (AS400) I was searching IBM's site to find some roadmap but didn't find anything yet. Do you have past experience on the older java release? ...
Can the JVM recover from an OutOfMemoryError without a restart
Can the JVM recover from an OutOfMemoryError without a restart if it gets a chance to run the GC before more object allocation requests come in? Do the various JVM implementations differ in this aspect? EDIT: My question was about the JVM recovering and not the user program trying to recover by catching the error. In other words if an...
JVM cannot use 8 CPUon Linux
I have observed that JVM cannot user 8 CPU advantage. Because when a thread runs more than 1 secs, other threds are waiting for it. there is no lock beetween these threds is there any jvm option for this ? ...
Does a java agent run in a separate thread?
I feel that this is something I should know, but does a java agent (specified with -javaagent) run in a separate thread? I've read that a Java agent is a pluggable library that runs embedded in a JVM and intercepts the classloading process, but I want to make sure: does it really intercept them (which sounds like it's running in another ...
Java Virtual Machines (JVM) and their performance comparison...
I was wondering if there somebody knows if there are some benchmarks which compare the following jvms. sun jvm vs. openjdk jvm vs. rockit jvm vs. j9 jvm vs. apache harmony. Which one is has the best performance? ...
Windows API in Java (Processing)? Do I need JVM?
I'm not sure I need JVM, or how'd I'd use it if I did. I basically want to a BFS for directories on a multi-drive system. I think I could pound this out using some of the Java examples I've found online, but if there is a faster, better way with Windows, I'd like to explore that option. Ideally I'd like it to work like the Window's Ex...
Keep JVM running on iseries
We are calling a Java program on a iseries machine and the first call to the program is quiet slow. The following calls are fast but if we wait a certain time the call is slow again. How can I keep the JVM up and running or is there another way to solve this problem? Thanks ...
How do clojure programs/compilers/interpreters actually "work"?
It seems that to install Clojure in every new IDE, I have to completely re-install it and create a copy of it. And running the REPL seems like it's running a Java program. I'm coming from a Ruby background, where Ruby programs are run by ruby program.rb, and the ruby being a program executed from one place, onto the file (I am aware th...
Run time exception handling (like Divide by zero) in JVM (Java)or CLR (C#)
Hello, How does JVM or for that matter CLR (Common language runtime) handles divided by zero? Does it check denominator every time, before executing divide instruction? Or is it handled using call back function which get invoked when "divide by zero" trap raised by processor? Any input will be appreciated. Thank you, Alan ...
Integers caching in Java
Possible Duplicate: Weird Java Boxing Hi guys, Recently I saw a presentation where was the following sample of Java code: Integer a = 1000, b = 1000; System.out.println(a == b); // false Integer c = 100, d = 100; System.out.println(c == d); // true Now I'm a little confused. I understand why in first case the result ...
Book Recommendation to learn more about Application Virtual Machines
I have always been intrigued and mystified by Virtual Machines and how they operate. I want to learn more about the inner workings of a virtual machine. Are there any good books on Virtual Machines/Virtual machine designs/Tour of a sample machine? How do I go about studying one? Do I pick up a spec for the JVM or start with the LLVM?...
Trigger Heap Dump of a 1.5 JVM running on Windows
I'm trying to diagnose a PermGen memory leak problem in a Sun One 9.1 Application Server. In order to do that I need to get a heap dump of the JVM process. Unfortunately, the JVM process is version 1.5 running on Windows. Apparently, none of the ways for triggering a heap dump support that setup. I can have the JVM do a heap dump after i...