Hi Folks, I have a java app that has a max heap of 1024M,it has perm gen space of 256M. Does it guarantee that this app will never use more than 1280M (1024+256) ? Does the stack memory also come from the heap size above or is it extra memory consumption? What if the java app uses native code that consumes memory then where does this...
I am doing some remote debugging with Eclipse attaching the a running JBoss server with EAR deployed. Most of the time, when I am connected to the remote JVM, I can hot-deploy my change, i.e. I can change the code in Eclipse and then it deploys. On some occasions, the JVM just crashes with the error below (if I save my code changes and...
Hello everyone, I am writing a Bytecode instrumenter. Right now, I am trying to find out how to do that in the presence of objects. I would like some clarifications on two lines I read in the JVMS (section 4.9.4): 1) "The verifier rejects code that uses the new object before it has been initialized." My question is, what does "u...
We're currently running ColdFusion 9 on a RedHat Enterprise Linux server and have found that, under certain circumstances, the JVM is crashing causing the CF server to be completely useless and requiring a full server restart. The only error that's being returned by the CF app just prior to the JVM completing its death spiral is a java....
I tried to run example from HornetQ and I got this error: [java] HornetQServer_0 out: Deployment "JNDIServer" is in error due to: java.rmi.server.ExportException: Port already in use: 1098 Actually this is not the first time I got this kind of error. I can verify that port 1098 is indeed already in use (using Netstat command) but I ...
We use java webstart on the client side for a java swing based aplication. Recently we have been experiencing a weird "Cannot start java Virtual machine " error when clicking in the jnlp link. We soon find out its because the max-heap-size setting in the jnlp file was set to 1024m whereas most of the clients PC only have 1 gb physical ...
It's possible to run double JVM on one computer? Then how to do? ...
I have a jar file. I want to know which external classes and methods is used by classes inside jar file. Can anyone suggest me any tool? For example import java.util.Vector; class MyJarClass{ public static void main(String args[]){ Vector v = new Vector(); AnotherClass another = new AnotherClass(); v.addEle...
Hi there. I'm in the process of learning Java, I'm reading the Head First Java book and I think it's great so far... However, one thing I really like to know is how much space does an object takes from the memory heap, you know... bits, bytes, kb, etc. How can this be done? This is my first question here... I hope isn't a stupid questi...
I already handled to start another VM in Java. See ProcessBuilder - Start another process / JVM - HowTo? For some reason, I can't manage to do the same in Scala. Here's my code object NewProcTest { def main(args :Array[String]) { println("Main") // val clazz = classOf[O3] val clazz = O4.getClass Proc.spawn(clazz, true...
I wrote a C program that starts a JVM using JNI_CreateJavaVM. The program is a Windows console application (VC 2008). JNI version is 1.6. If I debug the program and then stop the debugging in the middle, before it reaches the call to DestroyJavaVM then the CMD.exe window remains open and I'm unable to close or kill it. If I look at the ...
Hi all, An eclipse plugin for IBM RSM launches a java process to make some computations (realized in C/C++ via JNI). The problem here is when the process is started, it crashes...but only on windows. Moreover, if the process is started using Oracle/Sun jvm, it works fine. Under linux, java -version gives java version "1.6.0" Java(TM) S...
Are there specific frameworks for Jython or JRuby, or is it you can run a py or ruby app on the JVM? i.e. you take your python django app, and you can run in on tomcat using jython? Sorry little confused. ...
From PMD: IntegerInstantiation: In JDK 1.5, calling new Integer() causes memory allocation. Integer.valueOf() is more memory friendly. ByteInstantiation: In JDK 1.5, calling new Byte() causes memory allocation. Byte.valueOf() is more memory friendly. ShortInstantiation: In JDK 1.5, calling new Short() causes memory allocati...
The method System.identityHashCode(...) is called that way, because it identifies objects, so two distinct objects can't have same identity-hashcode, right? It returns an int. But what happens, on a system with huge amount of RAM, when the number of objects exceeds the integer range 2^32? Wouldn't it be a problem for HashMaps and HashS...
Here's a question from a Crystal n00b. Accessing a database using JDBC and using the Crystal 2008 SP1 user interface (File/Export etc) I was having problems running out of Java heap. I finally started digging around in the software install folders and stumbled across CRConfig.xml. It has lots of parameters like JVMMaxHeap, documented ...
How can I run PHP on JVM (akin to Jython and JRuby)? I am aware of the following: Quercus, which appears to be dead alive and well. Seems like I've been visiting the wrong website. webSphere sMash, that appears to have no documentation Is there a more mature project for this? ...
Hi I cannot for the life of me find a definition of what the Java VM flag CMSClassUnloadingEnabled actually does, other than some very fuzzy high-level definitions such as "gets rid of your PermGen problems" (which it doesn't, btw). I have looked on Sun's/Oracle's site, and even the options list doesn't actually say what it does. Base...
I've read detailed papers about the inner workings of the various garbage collectors in the JVM, but I've had trouble finding the same level of details for .NET's runtime... Anyone have links to good articles/research/pages on .NET's garbage collector? ...
Hi I know that the -server JVM flag causes the JVM to use the Server VM rather than the Client VM, however, according to some internal documentation at my workplace, the presence/absence of this flag causes Tomcat to do/not-do on-the-fly JSP compilation. Not knowing Tomcat that well, does anyone know if this is the case? My guess is th...