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Build Identifier: I am making an asynchronous HTTP POST request using HttpClient. Following is the snippet of the client code: ******************************** HttpClient client = new HttpClient(); client.setConnectorType(HttpClient.CONNECTOR_SELECT_CHANNEL); client.setThreadPool(new QueuedThreadPool()); client.start(); ContentExchange exchange = new ContentExchange() { protected void onResponseComplete() throws IOException { super.onResponseComplete(); int status = getResponseStatus(); if (status == 200){ byte[] response = this.getResponseContentBytes(); System.out.println("Read from Servlet response : " + new String(response)); } else{ System.out.println("Didn't get expected response"); } } }; exchange.setMethod("POST"); exchange.setURL("http://localhost:8080/MyServlet"); exchange.setRequestContent(new ByteArrayBuffer("hello from client")); client.send(exchange); ******************************** MyServlet returns the same string that I am passing in request. onResponseComplete received the correct response. But my client application doesn't exit. It keeps on running and I have explicitly kill the java process. Reproducible: Always Steps to Reproduce: 1. Use the above client with following simple servlet: *************************** import javax.servlet.http.*; import javax.servlet.ServletInputStream; import java.io.*; public class MyServlet extends HttpServlet { public void doPost(HttpServletRequest req, HttpServletResponse resp) { try{ byte[] input = new byte[req.getContentLength()]; ServletInputStream sin = req.getInputStream(); sin.readLine(input,0,input.length); sin.close(); System.out.println("Request content : " + new String(input)); resp.setContentLength(input.length); resp.setStatus(HttpServletResponse.SC_OK); resp.getOutputStream().write(input); } catch (IOException e) { } } public void doGet(HttpServletRequest req, HttpServletResponse resp) { doPost(req, resp); } } ***************************
Do you stop the HttpClient after you have received the response? It has a thread pool running and may be keeping the JVM running. Can you get a thread dump of the JVM after the response has been received? regards
(In reply to comment #1) > Do you stop the HttpClient after you have received the response? > It has a thread pool running and may be keeping the JVM running. > > Can you get a thread dump of the JVM after the response has been > received? > > regards My initial implementation of onResponseComplete() was closing the client. But client.close() in onResponseComplete() results in java.lang.InterruptedException with following stack: *********************************** java.lang.InterruptedException: sleep interrupted at java.lang.Thread.sleep(Native Method) at org.eclipse.jetty.util.thread.QueuedThreadPool.doStop(QueuedThreadPool.java:124) at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:80) at org.eclipse.jetty.client.HttpClient.doStop(HttpClient.java:501) at org.eclipse.jetty.util.component.AbstractLifeCycle.stop(AbstractLifeCycle.java:80) at MATLABArrayToHttp$1.onResponseComplete(MATLABArrayToHttp.java:34) at org.eclipse.jetty.client.HttpExchange$Listener.onResponseComplete(HttpExchange.java:850) at org.eclipse.jetty.client.HttpExchange.setStatus(HttpExchange.java:255) at org.eclipse.jetty.client.HttpConnection$Handler.messageComplete(HttpConnection.java:530) at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:752) at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:209) at org.eclipse.jetty.client.HttpConnection.handle(HttpConnection.java:239) at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:462) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436) at java.lang.Thread.run(Thread.java:619) *********************************** As you have requested, here's the thread dump after I receive the resopnse: *********************************** Full thread dump Java HotSpot(TM) Client VM (11.0-b16 mixed mode, sharing): "DestroyJavaVM" prio=6 tid=0x002b7800 nid=0x230 waiting on condition [0x00000000..0x0096fd4c] java.lang.Thread.State: RUNNABLE "qtp21091971-16" prio=6 tid=0x02ee4c00 nid=0x1764 waiting on condition [0x034bf000..0x034bfc94] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.eclipse.jetty.client.HttpClient$1.run(HttpClient.java:476) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436) at java.lang.Thread.run(Thread.java:619) "qtp21091971-15" prio=6 tid=0x02ee3400 nid=0xec8 waiting on condition [0x0346f000..0x0346fb94] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at org.eclipse.jetty.client.SelectConnector$1.run(SelectConnector.java:95) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436) at java.lang.Thread.run(Thread.java:619) "qtp21091971-14" prio=6 tid=0x02ee2000 nid=0x13ec waiting on condition [0x0341f000..0x0341fd14] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x22eba718> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:1963) at org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:320) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:451) at java.lang.Thread.run(Thread.java:619) "qtp21091971-13" prio=6 tid=0x02ee0c00 nid=0x1730 runnable [0x0338f000..0x0338fc14] java.lang.Thread.State: RUNNABLE at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method) at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(WindowsSelectorImpl.java:274) at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(WindowsSelectorImpl.java:256) at sun.nio.ch.WindowsSelectorImpl.doSelect(WindowsSelectorImpl.java:137) at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69) - locked <0x22ea91a8> (a sun.nio.ch.Util$1) - locked <0x22ea9198> (a java.util.Collections$UnmodifiableSet) - locked <0x22ea2b40> (a sun.nio.ch.WindowsSelectorImpl) at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80) at org.eclipse.jetty.io.nio.SelectorManager$SelectSet.doSelect(SelectorManager.java:497) at org.eclipse.jetty.io.nio.SelectorManager.doSelect(SelectorManager.java:180) at org.eclipse.jetty.client.SelectConnector.run(SelectConnector.java:179) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436) at java.lang.Thread.run(Thread.java:619) "qtp21091971-12" prio=6 tid=0x02edf800 nid=0x1404 waiting on condition [0x0333f000..0x0333fd94] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x22eba718> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:1963) at org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:320) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:451) at java.lang.Thread.run(Thread.java:619) "qtp21091971-11" prio=6 tid=0x02eb3800 nid=0x1124 waiting on condition [0x032ef000..0x032efa14] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x22eba718> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:1963) at org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:320) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:451) at java.lang.Thread.run(Thread.java:619) "qtp21091971-10" prio=6 tid=0x02edec00 nid=0x4a4 waiting on condition [0x0329f000..0x0329fa94] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x22eba718> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:1963) at org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:320) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:451) at java.lang.Thread.run(Thread.java:619) "qtp21091971-9" prio=6 tid=0x02b61800 nid=0xee8 waiting on condition [0x0324f000..0x0324fb14] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x22eba718> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:1963) at org.eclipse.jetty.util.BlockingArrayQueue.poll(BlockingArrayQueue.java:320) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:451) at java.lang.Thread.run(Thread.java:619) "Monitor Ctrl-Break" daemon prio=6 tid=0x02bdd800 nid=0x680 runnable [0x031bf000..0x031bfb94] java.lang.Thread.State: RUNNABLE at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(SocketInputStream.java:129) at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264) at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306) at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158) - locked <0x229c9640> (a java.io.InputStreamReader) at java.io.InputStreamReader.read(InputStreamReader.java:167) at java.io.BufferedReader.fill(BufferedReader.java:136) at java.io.BufferedReader.readLine(BufferedReader.java:299) - locked <0x229c9640> (a java.io.InputStreamReader) at java.io.BufferedReader.readLine(BufferedReader.java:362) at com.intellij.rt.execution.application.AppMain$1.run(AppMain.java:56) at java.lang.Thread.run(Thread.java:619) "Low Memory Detector" daemon prio=6 tid=0x02b12800 nid=0x11f4 runnable [0x00000000..0x00000000] java.lang.Thread.State: RUNNABLE "CompilerThread0" daemon prio=10 tid=0x02b0c800 nid=0x1044 waiting on condition [0x00000000..0x02dbf9bc] java.lang.Thread.State: RUNNABLE "Attach Listener" daemon prio=10 tid=0x02b0b000 nid=0x1ec runnable [0x00000000..0x00000000] java.lang.Thread.State: RUNNABLE "Signal Dispatcher" daemon prio=10 tid=0x02b09c00 nid=0x14b0 waiting on condition [0x00000000..0x00000000] java.lang.Thread.State: RUNNABLE "Finalizer" daemon prio=8 tid=0x02b04c00 nid=0x1228 in Object.wait() [0x02ccf000..0x02ccfa94] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x22e8d3b8> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:116) - locked <0x22e8d3b8> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:132) at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159) "Reference Handler" daemon prio=10 tid=0x02b00000 nid=0x1538 in Object.wait() [0x02c7f000..0x02c7fb14] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x22e8d440> (a java.lang.ref.Reference$Lock) at java.lang.Object.wait(Object.java:485) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116) - locked <0x22e8d440> (a java.lang.ref.Reference$Lock) "VM Thread" prio=10 tid=0x02afe800 nid=0x148 runnable "VM Periodic Task Thread" prio=10 tid=0x02b1cc00 nid=0x1308 waiting on condition JNI global references: 952 Heap def new generation total 960K, used 327K [0x22990000, 0x22a90000, 0x22e70000) eden space 896K, 29% used [0x22990000, 0x229d1cc0, 0x22a70000) from space 64K, 99% used [0x22a70000, 0x22a7fff8, 0x22a80000) to space 64K, 0% used [0x22a80000, 0x22a80000, 0x22a90000) tenured generation total 4096K, used 925K [0x22e70000, 0x23270000, 0x26990000) the space 4096K, 22% used [0x22e70000, 0x22f57570, 0x22f57600, 0x23270000) compacting perm gen total 12288K, used 2073K [0x26990000, 0x27590000, 0x2a990000) the space 12288K, 16% used [0x26990000, 0x26b965f8, 0x26b96600, 0x27590000) ro space 8192K, 67% used [0x2a990000, 0x2aef2d98, 0x2aef2e00, 0x2b190000) rw space 12288K, 53% used [0x2b190000, 0x2b800640, 0x2b800800, 0x2bd90000) ***********************************
(In reply to comment #1) > Do you stop the HttpClient after you have received the response? > It has a thread pool running and may be keeping the JVM running. > > Can you get a thread dump of the JVM after the response has been > received? > > regards Looks like Jetty is not happy about call to client.stop() from the onResponseComplete() handler. If I create another thread and have it call client.stop(), things work fine. So, I am changing the onResponseComplete() code to do the following after I read the response: Thread t = new Thread(){ public void run(){ try{ client.stop(); }catch(Exception ex){ } }; }; t.start();
that fix looks reasonable. the other approach would be to have your main thread wait on a Latch and have the onResponseComplete count down that latch. Main could then stop the client and exit. A final solution might be to flag the thread pool as a daemon thread pool, but that will probably mean that the JVM will exit as soon as the main finishes.
