avoid sync overhead each time null is checked - use double checked locking

git-svn-id: https://svn.apache.org/repos/asf/synapse/trunk@1610262 13f79535-47bb-0310-9956-ffa450edef68
1 file changed
tree: dcd6b919e0127a2345bf7cd4304e8477a9107b51
  1. java/
  2. scratch/