[jboss-user] [Javassist user questions] - NullPointerException in RuntimeSupport.DefaultMethodHandler.
pmeister
do-not-reply at jboss.com
Mon Sep 15 21:23:43 EDT 2008
I'm using javassist-3.8.1.GA with hibernate-core-3.3.0.SP1. I have a javassist problem that appears to occur when two different threads are doing a JavassistLazyInitializer.getProxy() on the exact same entity class + id but in two different sessions. One of the threads ends up in RuntimeSupport.DefaultMethodHandler.invoke() with the "proceed" argument set to null, which results in a NullPointerException. According to the javadoc for MethodHandler.invoke(), the proceed argument "is null if the overridden mehtod is abstract or declared in the interface", so I'm not sure why DefaultMethodHandler.invoke() doesn't check for null. But my guess is that there's some sort of race condition causing this.
Here's one thing that might provide a clue: JavassistLazyInitializer.getProxy() is calling Class.newInstance() to create a new instance of my entity class (Carrier). The failure happens when a final field is being initialized during construction of that instance. The final field is declared in an abstract parent class (AbstractCodeParentEntity), and is initialized by calling an inherited method (createStringFieldValue). In other words, my Carrier entity inherits this field:
private final FieldValue code = createStringFieldValue("code");
This failure always occurs when createStringFieldValue is executing, so perhaps that provides a clue as to why the "proceed" argument ends up being null.
Please let me know what other information I can provide to help diagnose the problem and whether you can suggest any workarounds.
Below I've included the stack of the two threads that were simultaneously suspended by a setting a conditional breakpoint in Eclipse when proceed == null. The first is the thread that hit the breakpoint.
Thread [btpool0-0] (Suspended (breakpoint at line 37 in RuntimeSupport$DefaultMethodHandler))
RuntimeSupport$DefaultMethodHandler.invoke(Object, Method, Method, Object[]) line: 37
Carrier_$$_javassist_70.createStringFieldValue(String) line: not available
Carrier_$$_javassist_70(AbstractCodeParentEntity).() line: 17
Carrier_$$_javassist_70(Organization).() line: 54
Carrier_$$_javassist_70(Carrier).() line: 17
Carrier_$$_javassist_70.() line: not available
NativeConstructorAccessorImpl.newInstance0(Constructor, Object[]) line: not available [native method]
NativeConstructorAccessorImpl.newInstance(Object[]) line: 39
DelegatingConstructorAccessorImpl.newInstance(Object[]) line: 27
Constructor.newInstance(Object...) line: 513
Class.newInstance0() line: 355
Class.newInstance() line: 308
JavassistLazyInitializer.getProxy(Class, String, Class, Class[], Method, Method, AbstractComponentType, Serializable, SessionImplementor) line: 139
JavassistProxyFactory.getProxy(Serializable, SessionImplementor) line: 72
PojoEntityTuplizer(AbstractEntityTuplizer).createProxy(Serializable, SessionImplementor) line: 402
JoinedSubclassEntityPersister(AbstractEntityPersister).createProxy(Serializable, SessionImplementor) line: 3483
DefaultLoadEventListener.createProxyIfNecessary(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType, PersistenceContext) line: 298
DefaultLoadEventListener.proxyOrLoad(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 219
DefaultLoadEventListener.onLoad(LoadEvent, LoadEventListener$LoadType) line: 126
SessionImpl.fireLoad(LoadEvent, LoadEventListener$LoadType) line: 905
SessionImpl.internalLoad(String, Serializable, boolean, boolean) line: 873
ManyToOneType(EntityType).resolveIdentifier(Serializable, SessionImplementor) line: 590
ManyToOneType(EntityType).resolve(Object, SessionImplementor, Object) line: 412
TwoPhaseLoad.initializeEntity(Object, boolean, SessionImplementor, PreLoadEvent, PostLoadEvent) line: 139
EntityLoader(Loader).initializeEntitiesAndCollections(List, Object, SessionImplementor, boolean) line: 877
EntityLoader(Loader).doQuery(SessionImplementor, QueryParameters, boolean) line: 752
EntityLoader(Loader).doQueryAndInitializeNonLazyCollections(SessionImplementor, QueryParameters, boolean) line: 259
EntityLoader(Loader).loadEntity(SessionImplementor, Object, Type, Object, String, Serializable, EntityPersister) line: 1881
EntityLoader(AbstractEntityLoader).load(SessionImplementor, Object, Object, Serializable) line: 71
EntityLoader(AbstractEntityLoader).load(Serializable, Object, SessionImplementor) line: 65
SingleTableEntityPersister(AbstractEntityPersister).load(Serializable, Object, LockMode, SessionImplementor) line: 3072
DefaultLoadEventListener.loadFromDatasource(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 434
DefaultLoadEventListener.doLoad(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 415
DefaultLoadEventListener.load(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 165
DefaultLoadEventListener.proxyOrLoad(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 223
DefaultLoadEventListener.onLoad(LoadEvent, LoadEventListener$LoadType) line: 126
SessionImpl.fireLoad(LoadEvent, LoadEventListener$LoadType) line: 905
SessionImpl.get(String, Serializable) line: 842
SessionImpl.get(Class, Serializable) line: 835
FullTextSessionImpl.get(Class, Serializable) line: 335
HivemindFullTextSessionWrapper.get(Class, Serializable) line: 302
$FullTextSession_11c689001bf.get(Class, Serializable) line: not available
$FullTextSession_11c689001c0.get(Class, Serializable) line: not available
BusinessServiceImpl.getById(Long, Class) line: 257
$BusinessService_11c6890013b.getById(Long, Class) line: not available
$BusinessService_11c6890013a.getById(Long, Class) line: not available
EligibilityListenerImpl(AbstractMessageListener).receiveMessage(Reader) line: 134
$EligibilityListener_11c68900134.receiveMessage(Reader) line: not available
$EligibilityListener_11c68900133.receiveMessage(Reader) line: not available
MessageListenerServlet.handlePost(HttpServletRequest, HttpServletResponse) line: 90
MessageListenerServlet(AbstractHttpServlet).doPost(HttpServletRequest, HttpServletResponse) line: 99
MessageListenerServlet(HttpServlet).service(HttpServletRequest, HttpServletResponse) line: 727
MessageListenerServlet(HttpServlet).service(ServletRequest, ServletResponse) line: 820
ServletHolder.handle(ServletRequest, ServletResponse) line: 487
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1097
HiveMindFilter(HiveMindFilter).doFilter(ServletRequest, ServletResponse, FilterChain) line: 172
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1088
ServletHandler.handle(String, HttpServletRequest, HttpServletResponse, int) line: 360
SecurityHandler.handle(String, HttpServletRequest, HttpServletResponse, int) line: 216
SessionHandler.handle(String, HttpServletRequest, HttpServletResponse, int) line: 181
WebAppContext(ContextHandler).handle(String, HttpServletRequest, HttpServletResponse, int) line: 729
WebAppContext.handle(String, HttpServletRequest, HttpServletResponse, int) line: 405
Server(HandlerWrapper).handle(String, HttpServletRequest, HttpServletResponse, int) line: 152
Server.handle(HttpConnection) line: 324
HttpConnection.handleRequest() line: 505
HttpConnection$RequestHandler.content(Buffer) line: 843
HttpParser.parseNext() line: 647
HttpParser.parseAvailable() line: 211
HttpConnection.handle() line: 380
SelectChannelConnector$ConnectorEndPoint(SelectChannelEndPoint).run() line: 395
QueuedThreadPool$PoolThread.run() line: 488
Thread [btpool0-2] (Suspended)
Class.getDeclaredMethods0(boolean) line: not available [native method]
Class.privateGetDeclaredMethods(boolean) line: 2427
Class.getDeclaredMethods() line: 1791
SecurityActions.getDeclaredMethods(Class) line: 29
RuntimeSupport.findMethod2(Class, String, String) line: 106
RuntimeSupport.findMethod(Object, String, String) line: 48
Carrier_$$_javassist_70.createStringFieldValue(String) line: not available
Carrier_$$_javassist_70(AbstractCodeParentEntity).() line: 17
Carrier_$$_javassist_70(Organization).() line: 54
Carrier_$$_javassist_70(Carrier).() line: 17
Carrier_$$_javassist_70.() line: not available
NativeConstructorAccessorImpl.newInstance0(Constructor, Object[]) line: not available [native method]
NativeConstructorAccessorImpl.newInstance(Object[]) line: 39
DelegatingConstructorAccessorImpl.newInstance(Object[]) line: 27
Constructor.newInstance(Object...) line: 513
Class.newInstance0() line: 355
Class.newInstance() line: 308
JavassistLazyInitializer.getProxy(Class, String, Class, Class[], Method, Method, AbstractComponentType, Serializable, SessionImplementor) line: 139
JavassistProxyFactory.getProxy(Serializable, SessionImplementor) line: 72
PojoEntityTuplizer(AbstractEntityTuplizer).createProxy(Serializable, SessionImplementor) line: 402
JoinedSubclassEntityPersister(AbstractEntityPersister).createProxy(Serializable, SessionImplementor) line: 3483
DefaultLoadEventListener.createProxyIfNecessary(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType, PersistenceContext) line: 298
DefaultLoadEventListener.proxyOrLoad(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 219
DefaultLoadEventListener.onLoad(LoadEvent, LoadEventListener$LoadType) line: 126
SessionImpl.fireLoad(LoadEvent, LoadEventListener$LoadType) line: 905
SessionImpl.internalLoad(String, Serializable, boolean, boolean) line: 873
ManyToOneType(EntityType).resolveIdentifier(Serializable, SessionImplementor) line: 590
ManyToOneType(EntityType).resolve(Object, SessionImplementor, Object) line: 412
TwoPhaseLoad.initializeEntity(Object, boolean, SessionImplementor, PreLoadEvent, PostLoadEvent) line: 139
EntityLoader(Loader).initializeEntitiesAndCollections(List, Object, SessionImplementor, boolean) line: 877
EntityLoader(Loader).doQuery(SessionImplementor, QueryParameters, boolean) line: 752
EntityLoader(Loader).doQueryAndInitializeNonLazyCollections(SessionImplementor, QueryParameters, boolean) line: 259
EntityLoader(Loader).loadEntity(SessionImplementor, Object, Type, Object, String, Serializable, EntityPersister) line: 1881
EntityLoader(AbstractEntityLoader).load(SessionImplementor, Object, Object, Serializable) line: 71
EntityLoader(AbstractEntityLoader).load(Serializable, Object, SessionImplementor) line: 65
SingleTableEntityPersister(AbstractEntityPersister).load(Serializable, Object, LockMode, SessionImplementor) line: 3072
DefaultLoadEventListener.loadFromDatasource(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 434
DefaultLoadEventListener.doLoad(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 415
DefaultLoadEventListener.load(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 165
DefaultLoadEventListener.proxyOrLoad(LoadEvent, EntityPersister, EntityKey, LoadEventListener$LoadType) line: 223
DefaultLoadEventListener.onLoad(LoadEvent, LoadEventListener$LoadType) line: 126
SessionImpl.fireLoad(LoadEvent, LoadEventListener$LoadType) line: 905
SessionImpl.get(String, Serializable) line: 842
SessionImpl.get(Class, Serializable) line: 835
FullTextSessionImpl.get(Class, Serializable) line: 335
HivemindFullTextSessionWrapper.get(Class, Serializable) line: 302
$FullTextSession_11c689001bf.get(Class, Serializable) line: not available
$FullTextSession_11c689001c0.get(Class, Serializable) line: not available
BusinessServiceImpl.getById(Long, Class) line: 257
$BusinessService_11c6890013b.getById(Long, Class) line: not available
$BusinessService_11c6890013a.getById(Long, Class) line: not available
EligibilityListenerImpl(AbstractMessageListener).receiveMessage(Reader) line: 134
$EligibilityListener_11c68900134.receiveMessage(Reader) line: not available
$EligibilityListener_11c68900133.receiveMessage(Reader) line: not available
MessageListenerServlet.handlePost(HttpServletRequest, HttpServletResponse) line: 90
MessageListenerServlet(AbstractHttpServlet).doPost(HttpServletRequest, HttpServletResponse) line: 99
MessageListenerServlet(HttpServlet).service(HttpServletRequest, HttpServletResponse) line: 727
MessageListenerServlet(HttpServlet).service(ServletRequest, ServletResponse) line: 820
ServletHolder.handle(ServletRequest, ServletResponse) line: 487
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1097
HiveMindFilter(HiveMindFilter).doFilter(ServletRequest, ServletResponse, FilterChain) line: 172
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1088
ServletHandler.handle(String, HttpServletRequest, HttpServletResponse, int) line: 360
SecurityHandler.handle(String, HttpServletRequest, HttpServletResponse, int) line: 216
SessionHandler.handle(String, HttpServletRequest, HttpServletResponse, int) line: 181
WebAppContext(ContextHandler).handle(String, HttpServletRequest, HttpServletResponse, int) line: 729
WebAppContext.handle(String, HttpServletRequest, HttpServletResponse, int) line: 405
Server(HandlerWrapper).handle(String, HttpServletRequest, HttpServletResponse, int) line: 152
Server.handle(HttpConnection) line: 324
HttpConnection.handleRequest() line: 505
HttpConnection$RequestHandler.content(Buffer) line: 843
HttpParser.parseNext() line: 647
HttpParser.parseAvailable() line: 211
HttpConnection.handle() line: 380
SelectChannelConnector$ConnectorEndPoint(SelectChannelEndPoint).run() line: 395
QueuedThreadPool$PoolThread.run() line: 488
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