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Threads not forking in a JUNIT test case

Jeff Gaer
Ranch Hand

Joined: Jun 04, 2001
Posts: 99
I have a Junit Test case that is testing some client server code. I create a separate threads to emulate the client and the server and expect to see operations interspersed. However they seemed to run sequentially. Running with debug on in eclipse, it looks as so all the Thread.run() calls are stacked in the same (main) thread. I would have expected that after the new Thread(new myRunnabled()).run a new thread to appear in the debug window. Here's is the stack trace from the main thread and its evident that after the run() methid is called the runnable is executing in the main thread.

The following code executes

Thread thread=new Thread(new Runner());

The first few lines of runnaer are

class Runner implements Runnable{

public void run() {
boolean first=true;
try {

I would expect Runnner to be running in its own thread, but the stack trace indicates it is exectuing in the main thread

Thread.run() line: 662
MockIS.play(String) line: 78
MockISTest$Runner.run() line: 140
Thread.run() line: 662
MockISTest.TestMockIS() line: 85

The full stack trace of the main thread follows.
Thread [main] (Suspended)
SocketInputStream.socketRead0(FileDescriptor, byte[], int, int, int) line: not available [native method]
SocketInputStream.read(byte[], int, int) line: 129
SocketInputStream.read() line: 182
AIResponse$Builder(AbstractMessageLite$Builder<BuilderType>).mergeDelimitedFrom(InputStream, ExtensionRegistryLite) line: 276
AIResponse$Builder(AbstractMessage$Builder<BuilderType>).mergeDelimitedFrom(InputStream, ExtensionRegistryLite) line: 705
AIResponse$Builder(AbstractMessageLite$Builder<BuilderType>).mergeDelimitedFrom(InputStream) line: 288
AIResponse$Builder(AbstractMessage$Builder<BuilderType>).mergeDelimitedFrom(InputStream) line: 697
AIResponse.parseDelimitedFrom(InputStream) line: 202
MockIS$Relay.run() line: 87
Thread.run() line: 662
MockIS.play(String) line: 78
MockISTest$Runner.run() line: 140
Thread.run() line: 662
MockISTest.TestMockIS() line: 85
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]
NativeMethodAccessorImpl.invoke(Object, Object[]) line: 39
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 25
Method.invoke(Object, Object...) line: 597
TestMethod.invoke(Object) line: 59
MethodRoadie.runTestMethod() line: 98
MethodRoadie$2.run() line: 79
MethodRoadie.runBeforesThenTestThenAfters(Runnable) line: 87
MethodRoadie.runTest() line: 77
MethodRoadie.run() line: 42
JUnit4ClassRunner.invokeTestMethod(Method, RunNotifier) line: 88
JUnit4ClassRunner.runMethods(RunNotifier) line: 51
JUnit4ClassRunner$1.run() line: 44
ClassRoadie.runUnprotected() line: 27
ClassRoadie.runProtected() line: 37
JUnit4ClassRunner.run(RunNotifier) line: 42
JUnit4TestClassReference(JUnit4TestReference).run(TestExecution) line: 50
TestExecution.run(ITestReference[]) line: 38
RemoteTestRunner.runTests(String[], String, TestExecution) line: 467
RemoteTestRunner.runTests(TestExecution) line: 683
RemoteTestRunner.run() line: 390
RemoteTestRunner.main(String[]) line: 197

Sun Certified Java Programmer Java 2<P>Jeff Gaer
Richard Tookey
Ranch Hand

Joined: Aug 27, 2012
Posts: 1064

You start() threads running so that should be

Just calling the run() method does as you say - it executes the code sequentially.
I agree. Here's the link: http://aspose.com/file-tools
subject: Threads not forking in a JUNIT test case