Double-checked locking in org.jboss.weld.util.BeansClosure#getClosure is a cause for NPE

Application deployment fails with a following exception:

05:33:26,201 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-7) MSC00001: Failed to start service jboss.deployment.unit."exp-cdi-injectApplication.war".WeldService: org.jboss.msc.service.StartException in service jboss.deployment.unit."exp-cdi-injectApplication.war".WeldService: java.lang.NullPointerException
at org.jboss.as.weld.services.WeldService.start(WeldService.java:83)
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [rt.jar:1.6.0_27]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [rt.jar:1.6.0_27]
at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_27]
Caused by: java.lang.NullPointerException
at org.jboss.weld.bootstrap.BeanDeployment.createBeans(BeanDeployment.java:194)
at org.jboss.weld.bootstrap.WeldBootstrap.deployBeans(WeldBootstrap.java:336)
at org.jboss.as.weld.WeldContainer.start(WeldContainer.java:82)
at org.jboss.as.weld.services.WeldService.start(WeldService.java:76)
... 5 more

Looking at the code that belongs to weld-core-1.1.5.AS71.Final, we can see the following at the lines 193-194 of BeanDeployment:

193: BeansClosure closure = BeansClosure.getClosure(this.beanManager);
194: closure.addEnvironment(this.beanDeployer.getEnvironment());

Which leads to a conclusion that closure is null (the lines prior to the mentioned ones show that beanDeployer itself couldn't be null).
Looking into BeansClosure#getClosure():

public static BeansClosure getClosure(BeanManagerImpl beanManager)
{
BeansClosure closure = (BeansClosure)closureMap.get(beanManager);
if (closure == null) {
synchronized (closureMap) {
if (!closureMap.containsKey(beanManager)) {
closure = new BeansClosure();
for (Iterable beanManagers : BeanManagers.getAccessibleClosure(beanManager)) {
for (BeanManagerImpl accessibleBeanManager : beanManagers)

{ closureMap.put(accessibleBeanManager, closure); }

}
}
}
}
return closure;
}

To prevent race conditions, maybe it makes sense to reside the full method body into synchronized block.