[TOMEE-1934] Incorrect double-check locking

• Type: Bug
• Status: Resolved
• Priority: Trivial
• Resolution: Auto Closed
• Flags: Patch
• Assignee: Unassigned
• Reporter: Svetlin Zarev
• Created: 14/Sep/16 07:29
• Updated: 17/May/23 18:52
• Resolved: 17/May/23 18:52

Description

http://www.cs.umd.edu/%7Epugh/java/memoryModel/DoubleCheckedLocking.html

 public BeanManagerImpl getBeanManagerImpl() {
        if (bm == null) { // should be done in the constructor
            synchronized (this) {
                if (bm == null) {
                    bm = new WebappBeanManager(this);
                }
            }
        }
        return bm;
    }

Unless *bm* is volatile, multiple instances of the bean manager can be created under concurrent conditions.

PS: I saw the suppress warning. I'm not sure if PMD just warns against DCL or that it was broken.

Issue Links

• links to: GitHub Pull Request #41