Hi Is there any way I can get a list of all the running Threads in the current JVM (including the Threads NOT started by my class)? Is it also possible to get the Thread and Class objects of all Thread in the list? I want to be able to do this through code. ...
Is there any way to determine how many threads can specific JVM + Application Server combination handle? The question is not only about web application request serving threads, but also about background threads. ...
Hi, I’m trying to quantify the difference in memory footprint of a small java app performing the same process multithreaded vs multiprocess. All my tests are on Linux. When running multithreaded, it is relatively easy to determine the overall footprint and additional overhead per thread. When running the single threaded process, the J...
To support a static-analysis tool I want to instrument or monitor a Java program in such a way that I can determine for every reflective call (like Method.invoke(..)): 1.) which class C this method is invoked on, and 2.) which classloader loaded this class C. Ideally I am looking for a solution that does not require me to statically m...
usecase example I have a servlet that is receiving login requests. If a login is currently in process OR the user is already logged in, the servlet should abort and inform the caller. current design Taking inspiration from database sharding, I plan to use the first character of each userid as a synchronization key. void login( Stri...
On analyzing my 4 days log of verbose, I get this Number of Global Garbage Collection: 0 Number of Scavenger Garbage Collection: 492 that's all? My tenured area is continuously full and memory leak is occurring. No GC attempt has been made to clear the memory Nursery area is always almost free/ empty (reason for low scavenger calls) ...
I've recently started learning Scala and was disappointed (but not surprised) that their generics are also implemented via type erasure. My question is, is it possible for Scala to have reified generics, or would the JVM need to be changed in some way? If the JVM does need to be changed, what exactly would need to be changed? ...
Is there any way to get a map or other data structure of the local variables in the current scope in on the JVM without using a debugger? That is, to get the locals of the current stack frame? I know that there are stacktrace objects, but StackTraceElement has no way to get access to any state. It just tells you what method was called ...
Specifically, in the case of object reference equality, what does the == operator do? Does the comparison return true if the references evaluate to the same object address at the time of comparison? Or does it utilize the hashCode value of the two references to determine if the objects are the same? To be very specific here, I would li...
Hi, Please consider the following java source: package com.stackoverflow; public class CondSpeed { private static final long COUNT = 1000000000; private static final long OUTER_COUNT = 15; private static long notEqOperator = 0L; private static long notOperator = 0L; private static long equalsFalse = 0L; public CondSpeed() { ...
Can someone explain the differences of the Java Platform SE (6), Java, Java VM, etc.? Thanks. ...
if we implement java interpreter in hardware then how we can achieve architecture neutrality of java bytecode... does java uses JIT(just in time interpreter) ? and how all this is related to Virtual Machine concept of operating system and java virtual machine(JVM) ...
I would like to get a reference to all objects in the Java heap, even if I don't immediately have a reference to those objects in my active thread. I don't need non-referenced objects (those "queued" for garbage collection), but would like to get anything that's still in use. The goal is to serialize and store all the objects to implem...
I had a question about Java Class Path variables. If I have multiple jars with the same classes, which one does the jvm use at runtime. The first one listed in the Class Path, the last one, or is undefined? Thanks ...
I have a situation where there is a small piece of Java code that has a large number of jars that it depends on. However, the dependencies inside these jars are very shallow. In most cases it only depends on a jar for a single interface. Instead of distributing all of the jars with the application, I would like to just distribute the sp...
We have production system going into infinite loop of full gc and memory drops form 8 gigs to like 1 MB in just 2 minutes. After taking heap dump it tells me there an is an array of java.lang.Object ([Ljava.lang.Object) with millions of java.lang.String objects having same String taking 99% of heap. But it doesn't tell me which class i...
The Java Virtual Machine Instruction Set page provides information about mnemonics such as aaload, aastore... etc. However neither the cpu cycles that these mnemonics would take up is mentioned nor is there any info on the byte size or word size of these mnemonics. Any idea where this information could be found? ...
Hi, Background: I've got a new eclipse installation and have installed the m2eclipse plugin. After startup m2eclipse generates the message: Eclipse is running in a JRE, but a JDK is required Following the instructions from here I've changed the eclipse.ini file to use the JDK JVM: -startup plugins/org.eclipse.equinox.launcher_1...
The JVM already had three Lisps before Clojure arrived on the scene: Kawa, Armed Bear and SISC. What gap does Clojure fill that was left by those Lisps? ...
I have out of memory issues with following environment: Tomcat 5.1.23 Using XFire WebServices Framework JDK 1.5 Used YourKit to profile it and found out multiple instances of class org.apache.tomcat.util.threads.ThreadWithAttributes has huge ArrayList object (Stack Local) with java.lang.Object array containing duplicate string. Follow...