Looks up the {@code SecurityManager} instance in the backing map without performing any non-null guarantees.
@return the {@code SecurityManager} in the backing map, or {@code null} if it has not yet been populated.
See Implementation
Looks up the {@code SecurityManager} instance in the backing map without performing any non-null guarantees.
@return the {@code SecurityManager} in the backing map, or {@code null} if it has not yet been populated.