Double checked locking in PolicyEngineImpl.java

Method createEndpointPolicyInfo() in rt/ws/policy/src/main/java/org/apache/cxf/ws/policy/PolicyEngineImpl.java contains a classic instance of the double checked locking pattern, which may cause an object to become visible to a different thread in a partially initialized state.

Please see The "Double-Checked Locking is Broken" Declaration (https://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html) to understand why this happens. A quick Google search should return several possible solutions.