deadlock

问题 //code taken from java concurrency in practice package net.jcip.examples; import java.util.concurrent.*; public class ThreadDeadlock { ExecutorService exec = Executors.newSingleThreadExecutor(); public class LoadFileTask implements Callable<String> { private final String fileName; public LoadFileTask(String fileName) { this.fileName = fileName; } public String call() throws Exception { // Here's where we would actually read the file return ""; } } public class RenderPageTask implements

问题 After reading this post a few months ago, I became paranoid of getting the Result of a Task<T> and incessantly wrapped all of my calls to it with a ConfigureAwait(false) or Task.Run . However, for some reason the following code completes successfully: public static void Main(string[] args) { var arrays = DownloadMany(); foreach (var array in arrays); } IEnumerable<byte[]> DownloadMany() { string[] links = { "http://google.com", "http://microsoft.com", "http://apple.com" }; using (var client =

问题 I'm having a problem with deadlock on SELECT/UPDATE on SQL Server 2008. I read answers from this thread: SQL Server deadlocks between select/update or multiple selects but I still don't understand why I get deadlock. I have recreated the situation in the following testcase. I have a table: CREATE TABLE [dbo].[SessionTest]( [SessionId] UNIQUEIDENTIFIER ROWGUIDCOL NOT NULL, [ExpirationTime] DATETIME NOT NULL, CONSTRAINT [PK_SessionTest] PRIMARY KEY CLUSTERED ( [SessionId] ASC ) WITH ( PAD_INDEX

问题 I'm having a problem with deadlock on SELECT/UPDATE on SQL Server 2008. I read answers from this thread: SQL Server deadlocks between select/update or multiple selects but I still don't understand why I get deadlock. I have recreated the situation in the following testcase. I have a table: CREATE TABLE [dbo].[SessionTest]( [SessionId] UNIQUEIDENTIFIER ROWGUIDCOL NOT NULL, [ExpirationTime] DATETIME NOT NULL, CONSTRAINT [PK_SessionTest] PRIMARY KEY CLUSTERED ( [SessionId] ASC ) WITH ( PAD_INDEX

问题 I'm using DBCP data source (with default configuration) in Spring configuration to manage my connections to the database, and I'm running into a deadlock condition when the number of clients increase. I found that there is a deadlock issue in DBCP 1.2.1 which I was using, which was supposed to be resolved in 1.4. So I upgraded to 1.4, but the issue still persists. In the thread dump, there are many threads blocked with the following stack trace on top: java.lang.Thread.State: WAITING on org

问题 One of the strategy to avoid deadlock situation in Java Multithreading is using timeout. Suppose, one thread has acquired lock on one resource and now waiting for lock on another resource. After certain time period if it can not acquire lock on resource2 then it should stop waiting for lock on resource2. Also it should release lock on resource1. Thus deadlocks will be avoided. But how to implement it in Java ? How to explicitly "release" lock ? How to define timeout to wait for lock. What is

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Re-entrant locks in C# If I write some code like this: class Program { static void Main(string[] args) { Foo(); Console.ReadLine(); } static void Foo() { lock(_lock) { Console.WriteLine("Foo"); Bar(); } } static void Bar() { lock(_lock) { Console.WriteLine("Bar"); } } private static readonly object _lock = new object(); } I get as output: Foo Bar I expected this to deadlock, because Foo acquires a lock, and then

问题 CAUTION: it is not a duplicate, please read topic сarefully https://stackoverflow.com/users/3448419/apangin quote: The real question is why the code sometimes works when it should not. The issue reproduces even without lambdas. This makes me think there might be a JVM bug. In the comments of https://stackoverflow.com/a/53709217/2674303 I tried to find out reasons why code behaves differently from one start to another and participants of that discussion made me piece of of advice to create a

问题 When I issued clrstack command, I got the following output. It is the callstack of a blocking thread which owns a deadlock and results in a deadlock. Is that its exact purpose? Does it have any other purposes (without any parameters). Where can I get more information? !clrstack OS Thread Id: 0x1b2c (6956) ESP EIP 0012f370 7c90e514 [HelperMethodFrame: 0012f370] System.Threading.Thread.SleepInternal(Int32) 0012f3c4 79299275 System.Threading.Thread.Sleep(Int32) 0012f3c8 00e0030f testlock

问题 Consider this code: public synchronized void onSignalsTimeout(List<SignalSpec> specs) { if (specs != null && specs.size() > 0) { for (SignalSpec spec : specs) { ParsedCANSignal timeoutedSignal = new ParsedCANSignal(); SignalsProvider.getInstance().setSignal(spec.name, spec.parent.parent.channel, timeoutedSignal); } } } I've got simple question: When Thread 1 calls onSignalsTimeout method, can Thread 2 access objects that are accessed in that method? Can't find anywhere if 'synchronized' locks