Problem I am using a completion service and spawning child threads to perform some ETL. As I debug in my IDE and then stop all processes, I notice I still have a bunch of zombie threads killing my CPU. This is due to the fact that I’m not terminating the child threads properly. Minimum Example Thoughts …
Tag: multithreading
How to set ThreadPoolTaskExecutor if sending numerous http requests at same time?
In my case, I need to send over million of http requests to client’s app for popping notification. like below sudo code I have referenced article from this website, and obtain a formula Number of threads = Number of Available Cores * (1 + Wait time / Service time) However, I think it’s not 100% su…
JNI 8 C++ : Thread attach and detach And async callback
How to async call Java method from std::thread ? Let’s assuming this is a IM bot sdk, Because it’s logic basicly a IM bot sdk. The most importtant is: How to async call java method and callback native. There is logic flow at the bottom, Maybe helpful. For example: Receive message A “backup&#…
Why Kotlin/Java doesn’t have an option for preemptive scheduler?
Heavy CPU bound task could block the thread and delay other tasks waiting execution. That’s because JVM can’t interrupt running thread and require help from programmer and manual interruption. So writing CPU bound tasks in Java/Kotlin requires manual intervention to make things run smoothly, like …
The strange behavior of the Java Deque in muti-thread environment
I wrote a simple demo code to test “how the Daemon Thread works”. But the demo shows another strange behavior: I make a Deque to hold the element called Event, and share it for two work threads, one add the element to the Deque. another check the Deque’s size and remove the element which is …
Which Thread.sleep commands pauses which threads?
I have four declarations of Thread.sleep(…) below. Each of the declarations is marked with that Line #1 to #6. My question is which declarations put which threads to pause? class Runa extends Thread{…
JavaFX Multithreading and Progressbar
I have a problem with freeze GUI. I’m a beginner with JavaFX and don’t know what I’m doing wrong. VideoToImages is background method from which I’m getting IntegerProperties to set progressBar value. …
Java happens-before relationship?
Consider the following code. Thread A calls run(), then another thread B calls test() and there shouldn’t be any happens-before relationship. I know it is not guaranteed that thread B sees the changes which thread A made. But is it possible that the output of this program is: Answer Yes, it’s poss…
How to use blocking queue in Spring Boot?
I am trying to use BlockingQueue inside Spring Boot. My design was like this: user submit request via a controller and controller in turn puts some objects onto a blocking queue. After that the consumer should be able to take the objects and process further. I have used Asnyc, ThreadPool and EventListener. Ho…
Accessing Java ThreadLocal object from a class other than where it was declared
I’m declaring a ThreadLocal object and setting a value like below. Is there anyway to reference this numberThreaLocalObj variable outside of this class within the same thread? I’ve found some code the seems to clear ALL the threadlocals, but I just need to clear this particular Threadlocal variabl…