Someone at work just asked for the reasoning behind having to wrap a wait inside a synchronized.
Honestly I can't see the reasoning. I understand what the javadocs say--that the thread ... |
Java's Object.wait() warns against "spurious wakeups" but C#'s Monitor.wait() doesn't seem to mention it at all.
Seeing how Mono is implemented on top of Linux and Linux has ... |
Why may this happen? The thing is that monitor object is not null for sure, but still we get this exception quite often:
java.lang.IllegalMonitorStateException: (m=null) Failed to get monitor for (tIdx=60)
...
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I've been having the worst time of my life trying to understand why this is happening, any input would be greatly appreciated.
The code in question runs in a diffrent thread then ... |
I am trying to figure out how to start and stop a serial interface.
class SerialInterface implements Runnable{
// Stream from file
@Override
public void run(){
try {
...
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I know that this is ill advised but still i am trying to look into a method of interrupting a thread which hangs, from another thread which is keeping time.
What i ... |
What happens to a Thread that fails to acquire a lock (non-spin)? It goes to the BLOCKED state. How does it gets executed again?
Lock lck = new ReentrantLock();
lck.lock()
try
{
}
finally
{
lck.unlock();
}
... |
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Normally when I ask for a thread dump, the symptoms of a poorly performing system are easily explained; i.e. normally I would be able to see that a number of threads ... |
java.lang.IllegalMonitorStateException is what I get with a nasty stack trace.
final Condition[] threads = new Condition[maxThreads];
myclass()
{
for (int i =0; i<maxThreads; i++)
...
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If wait can only be called from a synchronized context, and you can only call wait on an object while holding its lock, then how can multiple threads wait on the ... |
We have a junit test runner which timeout if one test is hanging. Now I want create a thread dump via API.
I know I can request the stacktraces via Thread.getAllStackTraces(). But ... |
In a servlet-based app I'm currently writing we have separate thread classes for readers and writers. Data is transmitted from a writer to multiple readers by using LinkedBlockingQueue<byte[]>, so a reader ... |
I am working on a multithreading app in Java 5. When it executes it starts several executor services and it has to run for a very long time. I have a ... |
I recently had a problem with three separate servers running the same code all experiencing the same symptoms. These are high volume REST / JSON servers that use json-lib to create ... |
In our production environments, we are using Thread Pool Executor to execute runntable task. I need to develop a Thread pool Heartbeat a monitoring system for Thread pool Executor Service:
Every ... |
Hi Lucy.Well,these two concepts are inter-related.A monitor is an object which enforces a certain policy about the execution of the code contained in it.This policy is that only one Thread should be able to execute it's code at a time.That is,only one thread of execution should be active in that monitor.In Java,this is done by using the synchronized keyword befor the ... |
i've heard these 4 words bandied about as if they were all synonyms. can someone please tell me what the differences between them are? when i go synchronized ( obj ) { /*...*/ } what am i actually "getting"? is it proper to say i'm getting "the lock belonging to obj" or "a lock on obj"? thanks! |
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Hello Java Guru's Scenario: The Classic Producer - Cubbyhole - Consumer example from Sun Microsystems public class ProducerConsumerTest { public static void main(String[] args) { CubbyHole c = new CubbyHole(); Producer p1 = new Producer(c, 1); Consumer c1 = new Consumer(c, 1); p1.start(); c1.start(); } } class CubbyHole { private int contents; private boolean available = false; public synchronized int get() ... |
Hi Chris! Normally, a monitor is on a high abstraction level than a lock. You could use a lock to control the access of a thread to a single resource. You open the lock, your thread enters, your thread exits, and you close the lock. A monitor usually is a more sophisticated thing that allows you things like readers-writers problem, producer-consumer ... |
Hi all, I have a small little app - client server type. The client is an applet sitting on a webserver. I'm just starting to do some testing here and I've run in to a fairly obvious problem. When I load the page the client connect to the server spawning a new thread on the server. If you would actually use ... |