jvm

Possible causes of Java VM EXCEPTION_ACCESS_VIOLATION?

When a Java VM crashes with an EXCEPTION_ACCESS_VIOLATION and produces an hs_err_pidXXX.log file, what does that indicate? The error itself is basically a null pointer exception. Is it always caused by a bug in the JVM, or are there other causes like malfunctioning hardware or software conflicts? Edit: there is a native component, this ...

What are the best JVM settings for Eclipse?

What are the best JVM settings you have found for running eclipse. Thanks! ...

Porting Android's Java VM to the iPhone?

Does anyone know of any existing projects that aim to port Android's Java VM over to the iPhone? From what I understand, this wouldn't be too out of reach and would certainly make for some exciting developments. Edit: I should point out that I am aware this will not happen using the official iPhone SDK. However, a jailbroken platform wo...

Explain the JVM Directory Layout on Mac OSX Leopard

Here is the directory layout that was installed with Leopard. What is the "A" directory and why the "Current" directory in addition to the "CurrentJDK"? It seems like you can easily switch the current JDK by move the CurrentJDK link, but then the contents under Current and A will be out of sync. lrwxr-xr-x 1 root wheel 5 Jun 14 ...

Why would you ever implement finalize()?

I've been reading through a lot of the rookie Java questions on finalize() and find it kind of bewildering that no one has really made it plain that finalize() is an unreliable way to clean up resources. I saw someone comment that they use it to clean up Connections, which is really scary since the only way to come as close to a guarant...

Will there be a functional language which does for the Java community what F# does for the .NET community?

Will there be a functional language which does for the Java community what F# does for the .NET community? What functional programming languages are available, or in development, for the JVM? ...

How do you design a good permgen space string in Java?

I'm wondering how you would go about designing a good permgen space string in Java. Based on my research and understanding I've come up with the following: example: JAVA_OPTS='-Xmx512m -XX:MaxPermSize=256m -server - Djava.awt.headless=true' sorry the example didn't paste when I first posted the question...... ...

Learning resources - stack machines, JVM especially

Hi, I'm curious if anyone have any really good tutorials/articles/books for learning about stack machines in general, and the JVM in particular. I know these ones: http://www.artima.com/insidejvm/applets/EternalMath.html http://www.ibm.com/developerworks/ibm/library/it-haggar_bytecode/ http://www.theserverside.com/tt/articles/article....

Java threads: Is it possible view/pause/kill a particular thread from a different java program running on the same JVM?

I have a program 'foo' running different threads, fooT1, fooT2, .. fooTn. Now if I want write another program 'bar', which could kill the thread fooTr, is that possible? Reason: One of the thread fooTr tracks product license. If this thread is killed; one may run this product indefinitely. And killing 'foo' itself is tolerable as 'foo'...

Real differences between "java -server" and "java -client"?

Is there any real practical difference between "java -server" and "java -client"? All I can find on Sun's site is a vague "-server starts slower but should run faster". What are the real differences? (Using JDK 1.6.0_07 currently.) ...

Appropriate Tomcat 5.5 start-up parameters to tune JVM for extremely high demand, large heap web application?

We have recently migrated a large, high demand web application to Tomcat 5.5 from Tomcat 4 and have noticed some peculiar slowdown behavior that appears to be related to JVM pauses. In order to run our application and support increased load over time on Tomcat 4, many not so standard JVM parameters were set and tuned as per the below, a...

64-bit JVM on Server, 32-bit JVM on Client, combination possible?

Hi, I'm having a JBoss EJB3 Application and a Swing client, running in 32-bit Java 6 VM's. We now have to change the Server JVM to 64 bit. May this combination of JVM's cause any trouble (do I need to use 64-bit JVM on the client, too)? Greetings, buzztee ...

Java Instantiation.

When an object is instantiated in Java, what is really going into memory? Are copies of parent constructors included? Why do hidden data members behave differently than overridden methods when casting? I understand the abstract explanations that are typically given to get you use this stuff correctly, but how does the JVM really do it...

Internals of Spring Framework and other IoC containers

I've been using spring for some time, but I always wondered how does it work, more specifically, how do they load and weave beans/classes marked only with an interface or @annotation. For the xml declarations, it's easy to see how spring preprocesses my beans (they are declared in the xml context that spring reads), but for the classes...

What can you not do on the Dalvik VM (Android's VM) that you can in Sun VM?

I know that you can run almost all Java in Dalvik's VM that you can in Java's VM but the limitations are not very clear. Has anyone run into any major stumbling blocks? Any major libraries having trouble? Any languages that compile to Java bytecode (Scala, Jython etc...) not work as expected? ...

What is the lightest Java Virtual Machine ever, except KVM?

I'd like to install Java on a Psion 5MX with GNU/Linux 16MB RAM machine, will it be possible? Unfortunatly, "KVM must be installed by the manufacturer". What I want is to be able to is to write basic Java code, test and sketch simple algorithms. Important notes: I don't need the graphic part since I'll only use the console (no graphic...

Java: How does the VM handle a 64bit `long` on a 32bit processor

How does the JVM handle a primitive "long", which is 64bits, on a 32bit processor? Can it utilise mulitple cores in parallel when on a Multi-Core 32bit machine? How much slower are 64bit operations on a 32bit machine? ...

JVM terminates when launching Eclipse MAT on Mac OS with J2SE 6.0

I have recently discovered the incredibly useful Eclipse Memory Analysis Tool, which makes quick work of finding memory leaks in Java applications. Unfortunately, after switching my JDK to 1.6 (under Mac OS 10.5), the JVM terminates immediately upon startup. All that appears is a dialog stating "JVM terminated" with "Exit code = -1". ...

What happens to an applet when browser is closed?

Hello, Let's suppose I have an applet running within a page in a browser. What happens when the browser is closed by the user? Is the applet notified so that it can perform some kind of close action on its side (closing connections opened to a server, cleaning static variables, ...)? Also, I assume the same behavior would apply for a ...

Best OS for java development?

What is the best OS for Java development? People from Sun are pushing the Solaris, yes Solaris have some extra features included in itself such as (dTrace, possibility for Performance tuning the JVM, etc.. ). Some friends of mine, had port their application on solaris, and they said to me that the performances was brilliant. I'm not happ...