Switching from JVM 1.4 to 1.5 has performance benefits as per release notes. http://java.sun.com/j2se/1.5.0/docs/relnotes/features.html#performance We have Java 1.4 compiled classes which are run on 1.5 JVM, will these classes suffer in performance because they were compiled using 1.4 ? ...
Is there a C or C++ compatible library for reading and writing Java class files? I.e. something like Apache BCEL. ...
I am doing a pmap on a tomcat process and I am seeing some huge anon blocks. From what I read anon blocks are used for thread stacks and for JNI. I have a very moderate thread count. How can I go about finding out what is causing these huge anon blocks? 00000000ee0d0000 26752K rwx-- [ anon ] 00000000efaf0000 33792K rwx-- [ anon...
How would you go about establishing where a class ( or maybe resource ) has been loaded from? I am trying to work out exactly where a class has been loaded from. Does anyone know if you can find out the following: Which Jar file did the class come from ? What classloader loaded the file? ...
We are hosting an application on SUN JVM that handles a lot of XML parsing using Jaxb. The application is parsing the XML fine using JRockit 5 but when using the SUN JVM the JVM spends a majority of it’s time on native methods such as java-lang.System.arraycopy, java.lang.String.intern and java.lang.ClassLoader.getPackage. The CPU load ...
We have a latency-sensitive application, and are experiencing some GC-related pauses we don't fully understand. We occasionally have a minor GC that results in application pause times that are much longer than the reported GC time itself. Here is an example log snippet: 485377.257: [GC 485378.857: [ParNew: 105845K->621K(118016K), 0.0...
I understand that the jvm is itself an application that turns the bytecode of the java executable into native machine code, but when using native threads I have some questions that I just cannot seem to answer. Does every thread create their own instance of the jvm to handle their particular execution? If not then does the jvm have to ...
How can I suspend the execution of a JVM for a configurable amount of time, similar to want happens on a full, serial, Garbage Collection? I want to test some edge cases but it's difficult to create the exact pauses I need with manually generating garbage + System.gc(). I'm trying to 'freeze' all the threads in the application, to sim...
Hi, I'm looking for a list of the common JVM options, specially for the apache tomcat container. Thank you, best regards Alex ...
I use Java Runtime.getRuntime().exec(command) to create a subprocess and print its pid as follows: public static void main(String[] args) { Process p2; try { p2 = Runtime.getRuntime().exec(cmd); Field f2 = p2.getClass().getDeclaredField("pid"); f2.setAccessible(true); System.out.println( f2.get( p2 ) ); } catch (...
Scala is a wonderful language, but I wonder how could be improved if it had it's own runtime? I.e. what design choices were made because of JVM choice? ...
I've been running grails for sometime without any issues but recently after an upgrade to Grails 1.1.1, I've encountered the dreaded PermGen errors. Prior to the upgrade, no such issue. The error seems to be happening when the <g:link> and <g:render> tags are used in a GSP although I'm not sure it's indicative that this is the issue but...
Will JVM throw exception when it runs classes compiled with a JDK that has same major version but higher minor version compared to JVM ? ...
I'm running java with the -verbose:gc option to measure garbage collector behavior, but it sends the info to stdout, mixing with my program's normal output. How do I tell it to output this info to stderr? ...
I am writing a DelegatingMetaClass that I would like to apply to all groovy classes in my project, but I do not how to get hold of all classes in the project? Here is the code: /* This will work ok, since I know Foo beforehand, but what about classes that do not exist yet? */ def myMetaClass = new DelegatingMetaClass(Foo.class) ...
Hi all, I would like to know if there is a way to, if best, prevent, or otherwise remove orphaned IBMJ9VM programmatically. It is mentioned in IBM's documentation that doing a CTRL-C will create orphan JVM process. Nicholas ...
I'm curious, why did Sun decide to make the JVM stack-based and Google decide to make the DalvikVM register based? I suppose the JVM can't really assume that a certain number of registers are available on the target platform, since it is supposed to be platform independent. Therefor it just postpones the register-allocation etc, to the ...
Hi All, How does jvm know what class an object is an instance of at runtime. I know we can use the getClass method to get the class name but how does the getClass method work? Thx, Praveen. ...
I have written a program to process packets. The program runs well if its run alone but when i integrate it to my main project the jvm crashes and shows the below result. What is the problem? # # An unexpected error has been detected by HotSpot Virtual Machine: # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x6d7dcf6e, pid=4328, tid...
We are trying to support Java enviroment on our embedded platform (700 MHz MIPS 74K, 128-256 MB memory). After reading this article and googling a bit, I came up with the shorted list: Java ME from Sun Kaffe Jbed Perc HP Chai VM PhoneME - seems the most promising one IBM WEME (Thanks to Thorbjørn Ravn Andersen) Aplix JBlend (Thanks to...