All Questions
48
questions
1
vote
1
answer
675
views
Java: Callback to main Thread
How can I make the callback execute in the "main thread"?
@Test
void threadTest() throws InterruptedException {
System.out.println("main thread:" + Thread.currentThread());
...
- 1,638
0
votes
1
answer
2k
views
How to properly do a thread callback in Java?
I am working on a project in Java (no Android). I have a thread that does some long work and I want a function in the main thread to be called when the work is done. I’ve seen many questions already ...
- 81
3
votes
1
answer
4k
views
kafka multi-threaded consumer with manual commit offset: KafkaConsumer is not safe for multi-threaded access
I use ArrayBlockingQueue to decouple Kafka consumers from sinks:
Multi-threaded consumption of Kafka, one kafka consumer per thread;
Kafka consumer manually manages the offset;
The Kafka consumer ...
- 77
0
votes
2
answers
2k
views
How ExecutorService works when submit a callable task with callback
How to add custom check in executorService.submit() callback.
I want my thread not to do anything, whenever flag is true. If flag is false then it should work as usual.
import org.apache.commons....
2
votes
2
answers
822
views
How to realize a callback in android?
Maybe my knowledge about this topic is so small, that the word "callback" is not right here, sorry about that.
If I start an thread in any class/activity/other thread and after finishing I want it to ...
- 121
1
vote
0
answers
29
views
Read data from a helper class' thread subclass
I'm trying to create a NFC reader on a helper class, made on a thread subclass which runs the code which calls a device API. I've been looking lots of questions already and code examples on the ...
- 11
3
votes
1
answer
1k
views
Reactive Programming in Java deep understanding
In order to have a deep understanding of Reactive Programming I was trying to reimplement, in a very simple way, the RxJava Observable class. This made me ask some important questions about reactive ...
- 3,117
0
votes
0
answers
132
views
Threads Callback return value
I have a class extending another class (which immplements Runnable) and implements a CallBack.
A value gets changed inside the Thread and I'd like to return it to the test() method. Is there a way to ...
- 11
0
votes
1
answer
1k
views
synchronize database queries java
Hi I have a java program with multiple threads querying an HSQL database. I'm getting some very weird results from the queries and my guess is that the database is not set up to handle many queries at ...
- 551
0
votes
1
answer
89
views
asynchronous programming using callbacks in android
I would like to know how can we do asynchronous programing in android, I read that asynchronous programming is not necessarily multithreaded(where this applies?), how can we do it in android because ...
- 6,247
1
vote
0
answers
632
views
Waiting for a callback method to be called in Android
I am writing an android application which interacts with a sensor using bluetooth and obtains temperature values. I am doing this by calling connectGatt() which is asynchronous and calls a callback ...
- 11
0
votes
0
answers
225
views
Wait for response in the main Java class after calling the instance and fuction in other Java class in Android Studio
Due to the delay in api call and response the data is not getting in time and I'm using delay to get reponse. If there the reponse is delayed more than my timer limit I get null error. Is there any ...
0
votes
0
answers
24
views
Keep Old Value in Catch Block in Java(Exception Handling) [duplicate]
Ok so here is the scenario from an interview I had recently. It took me a long time, but I still couldn't figure it out.
Suppose I have a standard try, catch finally block.
public int portNumber ...
- 173
0
votes
1
answer
2k
views
Java Spark: Non-blocking routes / callbacks with CompletableFutures
I have to make calls to long running methods in a Spark API implementation. These methods return CompletableFutures, so I'd like to free up the current Thread by triggering Spark to answer the client ...
- 436
0
votes
1
answer
112
views
synchronized on an object monitor or in my case is better a semaphore?
I have a doubt if my method is thread safe or not on the contrary I pretty sure is not thread safe, but I didn't yet found a solution.
The following is my code:
class TestLockSingleton
{
...
- 1,064