I test the simple test case under wildfly beta2, and got the stacktrace below,
Remove @Startup, the test case is pass.

@Singleton
@Startup
public class SSSManagerBean{
static Logger logger = Logger.getLogger(SSSManagerBean.class);

@Resource
private ManagedThreadFactory mtf;

public SSSManagerBean() {
}

@PostConstruct
public void postConstruct() {
logger.info("XXXXXXXXXXXXXXXXXXXXXXXXXX: "+mtf);
Thread t = mtf.newThread(new Runnable(){
@Override
public void run()

});
t.start();
}
}

The stacktrace:

Caused by: java.lang.IllegalStateException: JBAS016707: No concurrent context currently set, unable to locate the context service to delegate.
at org.jboss.as.ee.concurrent.DefaultContextSetupProviderImpl.getConcurrentContext(DefaultContextSetupProviderImpl.java:41) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.as.ee.concurrent.DefaultContextSetupProviderImpl.saveContext(DefaultContextSetupProviderImpl.java:48) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.glassfish.enterprise.concurrent.ManagedThreadFactoryImpl.newThread(ManagedThreadFactoryImpl.java:125)
at cn.org.gddsn.sss.server.SSSManagerBean.postConstruct(SSSManagerBean.java:91)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_25]
at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_25]
at org.jboss.as.ee.component.ManagedReferenceLifecycleMethodInterceptorFactory$ManagedReferenceLifecycleMethodInterceptor.processInvocation(ManagedReferenceLifecycleMethodInterceptorFactory.java:130) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doLifecycleInterception(Jsr299BindingsInterceptor.java:165) [wildfly-weld-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:148) [wildfly-weld-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:406)
at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:55) [weld-core-impl-2.1.0.CR1.jar:2013-09-26 16:53]
at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:84) [wildfly-weld-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.weld.injection.WeldInjectionInterceptor.processInvocation(WeldInjectionInterceptor.java:56) [wildfly-weld-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.ee.component.ManagedReferenceFieldInjectionInterceptorFactory$ManagedReferenceFieldInjectionInterceptor.processInvocation(ManagedReferenceFieldInjectionInterceptorFactory.java:115) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.ee.component.ManagedReferenceFieldInjectionInterceptorFactory$ManagedReferenceFieldInjectionInterceptor.processInvocation(ManagedReferenceFieldInjectionInterceptorFactory.java:115) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.ee.component.AroundConstructInterceptorFactory$1.processInvocation(AroundConstructInterceptorFactory.java:28) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.weld.injection.WeldInterceptorInjectionInterceptor.processInvocation(WeldInterceptorInjectionInterceptor.java:62) [wildfly-weld-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50) [wildfly-ee-8.0.0.Beta2-SNAPSHOT.jar:8.0.0.Beta2-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:273)
... 27 more